i

LAPORAN AKHIR

PENELITIAN KEMITRAAN

DANA ITS 2020

Produksi Hip Joint Prosthesis berbasis CoCrMo Alloy dengan

Investment Casting dalam rangka mencapai TKD

Tim Peneliti :

Yuli Setiyorini, ST., MPhil., PhD. Eng (Teknik Material dan Metalurgi/F.Indsys/ITS)

Sungging Pintowantoro, ST., MT., PhD (Teknik Material dan Metalurgi/F.Indsys/ITS)

Fakhreza Abdul, ST., MT (Teknik Material dan Metalurgi/F.Indsys/ITS)

DIREKTORAT RISET DAN PENGABDIAN KEPADA MASYARAKAT

INSTITUT TEKNOLOGI SEPULUH NOPEMBER

SURABAYA

2020

Sesuai Surat Perjanjian Pelaksanaan Penelitian No: 846/PKS/ITS/2020

i

LEMBAR PENGESAHAN LAPORAN AKHIR

1. Judul Penelitian : Produksi Hip Joint Prosthesis Berbasis Cocrmo Alloy Dengan

Investment Casting Dalam Rangkai Mencapai TKDN

2. Ketua Tim

a. Nama : Yuli Setiyorini S.T., M.Phil., Ph.D

b. Jenis Kelamin : Perempuan

c. NIP : 197907242005012003

d. Jabatan Fungsional : Lektor

e. Pangkat : Penata

f. Fakultas/Jurusan : Fakultas Teknologi Industri dan Rekayasa Sistem/ Teknik

Material dan Metalurgi

g. Laboratorium :

h. Tim :

No Nama Lengkap

Peran

Dalam

Tim

Fakultas/Jurusan/Unit Instansi/Perguruan

Tinggi

1 Dr. Sungging

Pintowantoro S.T.,M.T. Anggota

FT-IRS/Teknik Material dan

Metalurgi ITS

2 Fakhreza Abdul

S.T.,M.T. Anggota

FT-IRS/Teknik Material dan

Metalurgi ITS

3 Fahny Ardian Mahasiswa - ITS

4 Teguh Hari Prasetyo Anggota

Luar ITS -

PT. PELOPOR

TEKNOLOGI

IMPLANTINDO

3. Dana dan Waktu :

a. Jangka waktu program yang diusulkan : 2 Tahun

b. Biaya yang disusulkan : Rp. 120.000.000

c. Biaya yang disetujui tahun 2020 : Rp. 60.000.000

Menyetujui

Ketua Tim Peneliti

Yuli Setiyorini S.T., M.Phil., Ph.D

NIP. 197907242005012003

Mengetahui

Kepala Pusat Unggulan ITS Desain

Dr. Ir. Bambang Iskandriawan, M.Eng

NIP. 196011221990021001

Surabaya, 30 Nopember 2020

Menyetujui

Direktur Riset dan Pengabdian Masyarakat

Agus Muhamad Hatta, S.T, M.Si, Ph.D

NIP. 197809022003121002

ii

DAFTAR ISI

DAFTAR ISI.................................................................................................................................... iI

DAFTAR TABEL .......................................................................................................................... iiI

DAFTAR GAMBAR ...................................................................................................................... iv

DAFTAR LAMPIRAN ................................................................................................................... v

BAB I RINGKASAN ...................................................................................................................... 1

BAB II HASIL PENELITIAN ...................................................................................................... 2

BAB III STATUS LUARAN ....................................................................................................... 12

BAB IV PERAN MITRA ............................................................................................................. 13

BAB V KENDALA PELAKSANAAN PENELITIAN .............................................................. 14

BAB VI RENCANA TAHAPAN SELANJUTNYA .................................................................. 15

BAB VII DAFTAR PUSTAKA .................................................................................................... vi

BAB VIII LAMPIRAN ................................................................................................................. vii

iii

DAFTAR TABEL

Tabel 2.1 Mechanical Properties ...................................................................................................... 3

Tabel 2.2 Variabel Penelitian ........................................................................................................... 3

Tabel 2.3 Hasil Simulasi Static Structural ........................................................................................ 4

Tabel 2.4 Nilai Safety Factor dari simulasi ...................................................................................... 6

Tabel 2.5 Rumus menghitung nilai safety factor ............................................................................. 7

Tabel 2.6 Total Deformation ............................................................................................................ 8

Tabel 2.7 Input dan Output pada Analisa pemodelan ...................................................................... 9

Tabel 2.8 Input dan output pada Analisa transient thermal ............................................................ 10

iv

DAFTAR GAMBAR

Gambar 2.1 Desain Artificial Prosthesis ......................................................................................... 2

Gambar 2.2 Assembly dari AHP dengan tulang femur ................................................................... 2

Gambar 2.3 Model dari AHP dengam tulang femur dan hasil meshing di FEA ............................ 3

Gambar 2.4 Hasil Distribusi Tegangan pada desain implan ketebalan 15 mm .............................. 4

Gambar 2.5 Hasil Distribusi Tegangan pada desain implan ketebalan 14 mm .............................. 5

Gambar 2.6 Hasil Distribusi Tegangan pada desain implan ketebalan 13 mm .............................. 5

Gambar 2.7 Hasil Distribusi Tegangan pada desain implan ketebalan 12 mm .............................. 6

Gambar 2.8 S-N Kurva CoCrMo .................................................................................................... 7

Gambar 2.9 Desain AHP yang akan diproduksi.............................................................................. 9

Gambar 2.10 Desain Implan untuk simulasi Casting .................................................................... 11

Gambar 2.11 Hasil Simulasi Casting dengan Software ANSYS 19.1 .......................................... 11

v

DAFTAR LAMPIRAN

Lampiran 1 Tabel Daftar Luaran ................................................................................................... vii

Lampiran 2 Bukti i-MAMM 2020 ............................................................................................... viii

Lampiran 3 Bukti ICOMMET 2020 .............................................................................................. ix

Lampiran 4 Bukti Sertifikat Presentasi di ICOMMET 2020 ITS Surabaya ................................... x

Lampiran 5 Draft HKI .................................................................................................................... xi

Lampiran 6 Draft Paper Untuk ICOMMET 2020 ITS Surabaya .................................................. xx

Lampiran 7 Draft Paper Untuk I-MAM 2020 Universitas Indonesia ....................................... xxxii

1

BAB I RINGKASAN Tulang adalah organ dengan struktur kaku dan keras yang membentuk kerangka

manusia dan merupakan salah satu bagian dari tubuh manusia yang sangat vital peranannya.

Tulang memiliki beberapa fungsi antara lain sebagai alat gerak pasif penopang tubuh, proteksi,

mendasari gerakan, homeostasis mineral (penyimpanan dan pelepasan) dan memproduksi sel

darah [1]. Tulang manusia dapat mengalami beberapa masalah seperti penurunan kekuatan

(Osteop1orosis), terkena penyakit seperti kanker tulang dan arthritis, serta tulang manusia juga

dapat mengalami kehancuran karena kecelakaan atau benturan yang keras. Untuk kasus-asus

tersebut maka alternatif pengobatan yang diberikan kepada pasien adalah dengan mengantikan

tulang buatan (bone replacement) yaitu pemasangan implan (implantation) pada tubuh [2][3].

Pemilihan material implant sangatlah penting khususnya pada lokasi joint, seperti hip

prosthesis joint (tulang panggul), knee joint (tulang lutut), shoulder joint (tulang bahu) dan

spinal (tulang belakang). Pada lokasi joint sangat membutuhkan material yang memiliki

kekuatan (strength) dan ketahan gesek (wear resistance) yang bagus. Oleh karenanya produk

hip prosthesis joint yang akan dibuat pada penelitian ini akan menggunakan CoCrMo alloy.

Pemilihan CoCrMo alloy berdasarkan pada keunggulan ketahanan gesek yang cukup bagus

jika dibandingkan dengan stainless steel dan titanium alloy.

Selain itu design implant hip prosthesis joint juga sangat berpengaruh terhadap hasil

treatment pasien. Model metal-on-metal (MoM) yaitu tanpa menggunakan semen tulang

(cementless) lebih cocok untuk diaplikasikan pada pasien berumur muda yang memiliki

mobilitas tinggi dalam aktivitas. Sedangkan model MoM dengan menggunakan semen tulang

lebih sesuai untuk pasien usia lanjut, dimana aktivitas mobilitasnya tidak terlalu tinggi. Model

MoM dengan material yang sama (femur dan acetabular) dipilih dengan alasan untuk

mencegah korosi dalam tubuh menjadi parah [4]. Disamping itu, MoM juga dipilih sebagai

pertimbangan untuk mengantikan partikel release dari acetabular yang berbahan ceramic atau

polymer akibat gaya gesek. Geometries design juga sangat memegang peranan penting pada

proses penyembuhan dan kenyamanan pasien. Smart geometries sangat diperlukan untuk

mengurangi berat implant akibat densitas alloy, tanpa mengabaikan mechanical properties

implant dalam menerima beban. Oleh karenanya semua ini harus di simulasikan terlebih dahulu

sebelum proses manufacturing.

Investment casting dipilih sebagai alternative dalam proses manufacturing implant. Hal

ini dikarenakan untuk mengurangi ketergantungan bahan baku import yaitu berupa wrought

CoCrMo alloy dari proses cast forging. Selain itu, investment casting juga memiliki

keunggulan untuk dapat menghasilkan permukaan yang lebih halus. Untuk menunjang

kesuksesan dalam proses manufacturing, maka diperlukan simulasi casting terlebih dahulu.

Kegiatan penelitian ini dilakukan dalam upaya mewujudkan kemandirian mendesign,

mengembangkan material implant hip prosthesis joint, memproduksi dan memenuhi

permintaan kebutuhan implant yang tergantung terhadap produk import. Penelitian ini

diusulkan untuk dilaksanakan selama 2 tahun. Dimana pada tahun pertama bertujuan untuk

menentukan desain dan mengembangkan material CoCrMo alloy kemudian membuat

prototype untuk dilakukan uji coba. Pada tahun kedua dilakukan mulai dilakukan

manufacturing dengan pengembangan dan variasi design berdasarkan umur pasien (variasi

ukuran dan bentuk)

2

BAB II HASIL PENELITIAN Pada penelitian ini dilakukan percobaan untuk mengetahui nilai safety factor dari suatu

desain implant. Pertama dilakukan pembuatan model dari artificial hip prostheses

menggunakan software SolidWorks 2014 seperti yang ditampilkan pada gambar 2.1-2.3.

Desain implant dalam penelitian ini dilakukan variasi ketebalan dan variasi jumlah lubang pada

stem artificial hip prostheses. Dengan berkurangnya massa implant diharapkan akan mampu

mempercepat proses penyembuhan dan memperpanjang umur pakai dari implant tersebut.

Telah dilakukan simulasi dengan metode elemen hingga mengenai Artificial Hip Prosthesis

dengan material CoCrMo. Simulasi dilakukan menggunakan analisa model static structural

untuk mengetahui distribusi tegangan dan nilai deformasi dari masing – masing desain implant.

Untuk Analisa static structural dilakukan pembebanan sebesar 3000 N pada femoral head

dengan arah kebawah. Pembebanan statis ini mempresentasikan pasien dengan berat badan 70

kg. Selain itu beban sebesar 1250 N sebagai abductor muscle, 250 N sebagai ilio tibial tract.

Ujung bagian bawah dari tulang paha ditetapkan sebagai fix support. Finite elemen analisi dari

artificial hip prosthesis dilakukan menggunakan aplikasi software ANSYS 19.1 pada

Komputer P4 2.0 GHz Intel processor. Material yang dimasukkan pada FEA dianggap

memiliki sifat isotropic elasticity [5][6][7].

Gambar 2.1 Desain Artificial Hip Prosthesis.

Gambar 2.2 Assembly dari AHP dengam tulang femur

3

Gambar 2.3 Model dari AHP dengam tulang femur dan hasil meshing di FEA

Tabel 2.1 Mechanical Properties

Tabel 2.2 Variabel Penelitian

Materials Young’s Moudulus (GPa) Possion Ratio Yield Strength

Femur Bone 16,2 0,36 135

SS 316 L 193 0,3 170

CoCrMo (as cast) 210 0,3 448-517

Material Number of Hole Thickness (mm)

CoCrMo

0

12

1

2

3

4

0

13

1

2

3

4

0

14

1

2

3

4

0

15

1

2

3

4

4

Tabel 2.3 Hasil Simulasi Static Structural

Gambar 2.4 Hasil Distribusi Tegangan pada desain implan ketebalan 15 mm

Material Thickness Number of Hole Maximum Von Misses

Stress (MPa)

Yield Strength

(MPa)

CoCrMo

12

0 490,69

448

1 514,82

2 499,8

3 495,2

4 495,74

13

0 399,38

1 402,2

2 416,18

3 400,02

4 403,67

14

0 324,81

1 321,18

2 296,5

3 319,16

4 317,81

15

0 279,23

1 272,07

2 337,18

3 482,14

4 314,04

5

Gambar 2.5 Hasil Distribusi Tegangan pada desain implan ketebalan 14 mm

Gambar 2.6 Hasil Distribusi Tegangan pada desain implan ketebalan 13 mm

6

Gambar 2.7 Hasil Distribusi Tegangan pada desain implan ketebalan 12 mm

Dari hasil simulasi dengan software ANSYS 19.1 didapatkan hasil distribusi tegangan

yang berbeda dari tiap desain. Distribusi tegangan pada implan harus lebih rendah daripada

kekuatan luluh (yield strenth) material. Dalam Analisa static struktur, Tegangan Von Misses

Maksimum dalam desain AHP yang dihasilkan ditunjukkan pada Gambar 2.4-2.7. Berdasarkan

hasil simulasi desain AHP berbahan dasar CoCrMo menunjukkan bahwa beberapa desain

mengalami kegagalan karena hasil distribusi tegangan yang dialami melebihi nilai yield

strength seperti yang ditunjukkan pada Tabel 2.3. Desain dengan ketebalan 15 dan 1 lubang

terbuat dari CoCrMo adalah desain terbaik untuk pembebanan statis [8][9].

Tabel 2.4 Nilai Safety Factor dari simulasi

Material Thickness Number of Hole Goodman Soderberg Gerber

CoCrMo

12

0 0,828562 0,724638 1,024513

1 0,78972 0,69067 0,976483

2 0,813461 0,71143 1,005842

3 0,821013 0,718037 1,015179

4 0,82012 0,717255 1,014075

13

0 1,017994 0,89031 1,258745

1 1,010865 0,884072 1,249934

2 0,976896 0,854369 1,207926

3 1,016372 0,888889 1,256741

4 1,007174 0,880848 1,245365

14

0 1,251709 1,09471 1,547733

1 1,265883 1,107095 1,56527

2 1,273335 1,113613 1,574484

3 1,273884 1,114097 1,575158

4 1,279282 1,118823 1,581829

15

0 1,456047 1,273412 1,800402

1 1,494368 1,306925 1,847788

2 1,20579 1,05455 1,490956

3 0,843249 0,737485 1,042671

4 1,294648 1,132258 1,600831

7

Desain implan yang sangat baik harus memenuhi umur kelelahan maksimum atau infinite life.

Ini hanya dapat dipastikan dengan pengujian fisik atau analisis kelelahan. Dalam studi ini, umur

kelelahan implan pada hingga diprediksi menggunakan software komputer ANSYS Workbench.

Perhitungan kelelahan implan dilakukan untuk material CoCrMo. Dalam perhitungan fatik, digunakan

model material fatigue yang ditunjukkan pada Gambar 2.8. Umur kelelahan implan ditentukan

berdasarkan teori Goodman, Soderberg dan Gerber. Pendekatan umur stres (S / N) digunakan untuk

menghitung umur kelelahan implan. Formula ini berguna untuk proses awal pemilihan bahan implan

yang akan mengalami kondisi pembebanan siklik yang tinggi. Keuntungan dari pendekatan ini adalah

bahwa pendekatan ini mewakili inisiasi dan penyebaran retakan di lingkungan yang agresif. Dalam

model elemen hingga, bahan (tulang, logam dan semen) dianggap elastis dan analisis dilakukan menurut

kriteria umur tak hingga (109 siklus). Oleh karena itu, distribusi tegangan maksimal dipastikan lebih

rendah dari tegangan terendah pada kurva S / N. Pada Tabel 2.4, N menunjukkan faktor keamanan

untuk umur kelelahan dalam siklus pembebanan, Se untuk batas daya tahan dan Su untuk kekuatan tarik

akhir material. Tegangan rata-rata 𝜎𝑚 dan tegangan bolak-balik 𝜎𝑎 masing-masing didefinisikan

sebagai [4][6].

𝜎𝑚 =(𝜎𝑚𝑎𝑥+𝜎𝑚𝑖𝑛)

2 (1)

𝜎𝑎 =(𝜎𝑚𝑎𝑥− 𝜎𝑚𝑖𝑛)

2 (2)

N = Safety Factor

Se = Endurance Limit (MPa)

Su = Ultimate Tensile Strength (MPa)

𝝈𝒎 = Mean Stress (MPa)

𝝈𝒂 = Alternating Stress (MPa)

Tabel 2.5 Rumus menghitung nilai safety factor

Gambar 2.8 S-N Kurva CoCrMo

Fatigue Theories Formulas

Goodman (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑢

) =1

𝑁

Soderberg (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑦

) =1

𝑁

Gerber (𝑁. 𝜎𝑎

𝑆𝑒

) + (𝑁. 𝜎𝑚

𝑆𝑢

)2

= 1

8

Tabel 2.6 Total Deformation

CoCrMo lebih baik dari yang lain dalam hal umur kelelahan. Karena desain ini

memiliki nilai faktor keamanan yang lebih Dari Tabel 2.4 dapat dilihat bahwa semua desain

AHP baru memiliki nilai faktor keamanan yang berbeda sesuai dengan semua kriteria

kelelahan. Ini berarti bahwa beberapa desain AHP adalah desain yang buruk dan mungkin

gagal dalam pembebanan statis. Di antara desain AHP baru, desain AHP dengan ketebalan 15

mm dan 1 lubang berbahan tinggi di semua teori faigue. Nilai deformation dari design AHP

dan tulang femur diberikan pada Tabel 2.6. [7][8].

Desain AHP memiliki geometri ketebalan yang bervariasi dan jumlah lubang yang bervariasi.

Desain AHP baru pertama memiliki geometri standar tanpa lubang. Desain AHP lainnya memiliki

beberapa lubang pada bagian stem. Jumlah lubang dan ketebalan yang bervariasi dirancang untuk

mengurangi berat implan dan untuk menempelkan implan ke tulang femur dengan aman juga

meningkatkan proses osseointerasi. Desain AHP terbaik untuk kelelahan akibat pembebanan statis

adalah desain AHP dengan ketebalan 15 mm dan 1 lubang yang terbuat dari material CoCrMO [4].

Tahun pertama fokus pada pembuatan desain yang digunakan untuk implant. Setelah

pembuatan desain artificial hip joint selesai maka dilanjutkan dengan proses simulasi

menggunakan software ANSYS 2019. Analisis ini digunakan untuk mensimulasikan fenomena

yang akan terjadi pada saat pembuatan model.

Material Thickness Number of Hole Total Deformation (mm)

CoCrMo

12

0 13,914

1 13,848

2 13,77

3 13,706

4 13,658

13

0 14,149

1 14,068

2 14,007

3 13,952

4 13,908

14

0 14,228

1 14,156

2 14,092

3 14,04

4 13,996

15

0 14,075

1 13,99

2 13,919

3 13,855

4 13,812

9

Gambar 2.9 Geometri dan desain Artificial Hip Joint yang akan diproduksi dengan metode

investment casting

Permodelan pertama dilakukan dengan menggunakan analisa transient thermal untuk

mengetahui distribusi temperatur. Selanjutnya, dilakukan analisa couple-field dengan transient

structural. Analisa coupled field dapat merepresentasikan efek termal untuk dikaitkan pada

fenomena lain. Analisa transient structural kemudian dilakukan untuk mengetahui tegangan

termal dan shrinkage yang terjadi pada produk. Analisa termal pada permodelan ini

menggunakan program Ansys Workbench 19.1 dengan modul transient thermal. Analisa

transient thermal menentukan temperatur dan besaran termal lain yang berubah terhadap

waktu. Sebuah analisa transient thermal pada dasarnya memiliki prosedur yang sama dengan

analisa steady-state thermal, perbedaan utama diantara keduanya adalah sebagian besar

pembebanan pada analisa transient adalah fungsi terhadap waktu. Tabel 6.1 menunjukkan

beberapa sifat dari material yang harus dimasukkan ke dalam permodelan untuk mendapatkan

output yang diinginkan [9][10].

Tabel 2.7 Input dan output pada Analisa permodelan

Analisa Modul Input Output

Termal Transient Thermal

Konduktivitas termal,

koefisien panas spesifik,

densitas

Distribusi temperatur

Struktural Transient

Structural

Modulus elastisitas, poisson

ratio, koefisien ekspansi

termal

Tegangan termal,

shrinkage

10

Sebelum dilakukan investment casting akan kita lakukan Analisa permodelan

menggunakan ANSYS. Permodelan pada investment casting dilakukan dua tahap. Permodelan

pertama dilakukan dengan menggunakan analisa transient thermal untuk mengetahui distribusi

temperatur. Selanjutnya, dilakukan analisa couple-field dengan transient structural. Analisa

coupled field dapat merepresentasikan efek termal untuk dikaitkan pada fenomena lain. Analisa

transient structural kemudian dilakukan untuk mengetahui tegangan termal dan shrinkage

yang terjadi pada produk Investment Casting. Analisa termal pada permodelan ini

menggunakan program Ansys Workbench 19.1 dengan modul transient thermal. Analisa

transient thermal menentukan temperatur dan besaran termal lain yang berubah terhadap

waktu. Sebuah analisa transient thermal pada dasarnya memiliki prosedur yang sama dengan

analisa steady-state thermal, perbedaan utama diantara keduanya adalah sebagian besar

pembebanan pada analisa transient adalah fungsi terhadap waktu. Tabel dibawah ini

menunjukkan beberapa sifat dari material yang harus dimasukkan ke dalam permodelan untuk

mendapatkan output yang diinginkan [10].

Tabel 2.8 Input dan output pada analisa transient thermal

Analisa Modul Input Output

Termal Transient

Thermal

Konduktivitas termal, koefisien

panas spesifik, densitas Distribusi temperatur

Struktural Transient

Structural

Modulus elastisitas, poisson

ratio, koefisien ekspansi termal

Tegangan termal,

shrinkage

Analisa termal yang pertama adalah analisa mengenai distribusi temperatur pada hasil

coran. Shrinkage merupakan peristiwa menyusutnya volume selama proses pengecoran setelah

dilakukan pendinginan. Untuk menghitung shrinkage yang terjadi selama pendinginan,

diperlukan nilai deformasi pada hasil coran di setiap sumbu. Selanjutnya, geometri awal

produk dikurangi dengan deformasi tersebut sehingga didapatkan volume akhir produk.

Dengan mengurangkan volume awal dengan volume akhir, maka didapatkan besarnya

shrinkage pada produk investment casting. Selain itu dilakukan juga simulasi menggunakan

modul Static Structural yang bertujuan untuk mengetahui kekuatan produk, dari artificial hip

joint dengan berbagai pembebanan (berdiri, duduk, berjalan, melompat dan berlari). Apabila

hasil analisa ANSYS sudah menunjukkan hasil yang seperti apa yang dinginkan maka proses

selanjutnya berupa pengecoran dengan metode investment casting dengan bahan logam

CoCrMo [11][12]. Kemudian dilakukan pelapisan hidroksi apatit untuk meningatkan

kemampuan biocompatibility. Alasan pemakaian material CoCrMo adalah karena material

jenis ini memiliki sifat mekanik yang naik, lebih ringan dan memiliki ketahanan korosi yang

baik. Sedangkan proses pelapisan (coating) menggunakan hidroksiapatit adalah untuk

meingkatkan fixation antara artificial hip joint dengan femur bone dan juga mengurangi laju

munculya debris yang disebabkan mekanik maupun chemical [13][14].Untuk kegiatan

pengecoran dengan metode investment casting dan proses coating dilakukan di PT. Pelopor

Teknologi Implantindo, Mojokerto, Jawa Timur.

11

Gambar 2.10 Desain Implan untuk simulasi Casting

Gambar 2.11 Hasil Simulasi Casting demgam Software ANSYS 19.1

12

BAB III STATUS LUARAN Penelitian ini telah memiliki luaran berupa:

1. International Conference

Penelitian ini telah diikutkan pada acara International Meeting on Advances in Materials

(i-MAM) 2020 yang diadakan oleh Departemen Teknik Metalurgi dan Material, Fakultas

Teknik, di Universitas Indonesia yang telah dipresentasikan pada tanggal 16-17 Nopember

2020. Paper yang akan dipresentasikan berjudul “Finite Element Analysis of New Artificial

Hip Joint Design. Selain itu paper dengan judul “Finite Element Analysis of New Design

Artificial Hip Prosthesis” juga telah presentasikan pada acara “The 4th International Conference

on Materials and Metallurgical Engineering and Technology (ICOMMET) 2020” yang akan

dipresentasikan pada tanggal 19-20 Oktober 2020.

2. Hak Paten Sederhana

Penelitian ini telah menghasilkan suatu desain imlan tulang pinggul (artificial hip joint),

kemudian desain ini telah didaftarkan Hak Paten oleh pihak LPPM ITS.

3. Jurnal Internasional

Penelitian ini akan di submit ke Jurnal International terindeks Scopus (Minimal Q2), untuk

proses kemajuan dari pembautan Jurnal Internasional ini masih dalam pembuatan draft dan

proses simulasi dan pengumpulan data untuk melengkapi draft.

4. Thesis

Penelitian ini akan dibuat pula sebagai Thesis oleh mahasiswa S2 Teknik Material dan

Metalurgi atas nama Fahny Ardian (02511950010004). Untuk progress kemajuan dari thesis

ini telah sampai pada bab 3 dan rencananya akan dilakukan seminar proposal pada Januari

2021.

Selain luaran diatas, penelitian ini juga menghasilkan luaran beruapa beberapa desain baru

dari artificial hip prosthesis bagi PT. Pelopor Teknologi Implantindo yang nantinya akan dapat

diproduksi untuk memenuhi kebutuhan implant dalam negri dengan berbagai ukuran dan

geometri yang beragam.

13

BAB IV PERAN MITRA

Pada penelitian ini dilakukan dengan bantuan mitra yaitu PT. Pelopor Teknologi

Implantindo Mojokerto. Mitra tersebut dalam penelitian ini memiliki beberapa peran dan tugas

antara lain:

1. Melakukan pengujian awal dari material bahan baku

2. Melakukan desain implant

3. Melakukan pengecoran implant dari desain yang telah dilakukan simulasi dengan

ANSYS

4. Melakukan pengujian komposisi dari produk implant hasil investment casting

14

BAB V KENDALA PELAKSANAAN PENELITIAN Kendala yang dialami pada saat penelitian adalah keterbatasan perangkat computer

untuk dapat melakukan simulasi dengan software ANSYS 19.1 dan karena pandemi COVID

19 maka akses untuk melakukan penelitian di laboratorium di ITS sangat terbatas. Selain itu

kami juga mengalami kendala dalam pengadaan bahan baku karena masalah pengiriman yang

terhambat karena adanya pandemic COVID 19.

15

BAB VI RENCANA TAHAPAN SELANJUTNYA

Rencama tahapan selanjutnya dari penelitian adalah adalah melakukan pengembangan

dari segi desain implant dan metode produksinya serta pelapisan implant buatan dengan

Chitosan. Kemudian dilakukan pengujian in vitro dan in vivo pada produk implant. Tujuan

dari pengujian in vivo dan in vitro ini untuk mengetahui kemampuan mekanik dan

biokompatibilitas dari produks implant ini. Apabila semua pengujian telah selesai dan

menunjukkan hasil yang baik akan dilakukan produksi massal bekerja sama dengan PT.

Pelopor Teknologi Implantindo, Mojokerto, Jawa Timur.

vi

BAB VII DAFTAR PUSTAKA

[1] Rogerz, Kara.2011. Bone and Muscle Structure, Force and Motion. Britannica

Educational Publishing. New York

[2] www.Kemenkes.go.id

[3] World Health Organization FRAX, Calculation, 2011

[4] Colic, K. 2016. The Current Approach to Research and Design of The Artificial

Hip Prothesis. University of Berlgarde, Innovation Center. Serbia

[5] Smallman. & A.H.W. Ngan, 2007. Physical Metallurgy and Advanced Material,

Sevent Edition. Elsevier Science and Sabre Foundation Book

[6] Iyer, Mohan. 2018, The Hip Joint in Adults Advance and Developments, Pan

Stanford Publishing Pte. Ltd. Singapore

[7] Hasirci, Vasif. 2018. Fundamentals of Biomaterials, Springer Science. New York

[8] Buddy D, Ratner. 2013. Biomaterials Science an Introduction to Materials in

Medicine. Third Edition, Elsevier Science and Sabre Foundation Book.

[9] Park, John and Lakes. 2007. Biomaterials in Introduction. Third edition. Vol 1.USA

CRC Press

[10] Xiaolin. 2019. Finite Element Modelling and Simullation with ANSYS Workbench.CRC Press.

London

[11] Campbell. 2015. Complete Casting Handbook.Elsevier.Ltd.USA

[12] Carmen. 2019. Support Vector Representation Machine for Superalloy Investment

Casting Optimization. Department of Engineering and Architecture, University of

Trieste. Italy

[13] Nabakumar, Pramanik, Mishra, Indranil, Tapas Kumar, Parag Bhargava. 2009.

Chemical Synthesis, Characterization, and Biocompatibility Study of

Hidroxyapatite/Chitosan Phosphate Nanocomposite for Bone Tissue Engineering

Application. International Journal of Biomaterials. Volume Article ID 512417

[14] Yildrim, Oktay. 2004. Preparation and Characterization of Chitosan/Calsium

Phosphate Bases Composite, Turkey.

vii

BAB VIII LAMPIRAN

Lampiran 1. Tabel Daftar Luaran

TABEL DAFTAR LUARAN

Program : Penelitian Kemitraan

Nama Ketua : Yuli Setiyorini, S.T., MPhil., Ph.D. Eng.

Judul : Produksi Hip Joint Prosthesis berbasis CoCrMo Alloy dengan Investment Casting

dalam rangka mencapai TKD

1. Artikel Jurnal

No Judul Artikel Nama Jurnal Status Kemajuan

1 Artificial Hip Prosthesis Simulation

Using FEA

Material and

Design(Q1) Persiapan Draft

2. Artikel Konferensi

No Judul Artikel

Detail Konferensi (Nama

Penyelenggara, tempat,

tanggal)

Status Kemajuan

1

Finite Element Analysis of

New Design Artificial Hip

Prosthesis

Departemen Teknik

Material dan Metalurgi, ITS

Surabaya. 19-20 Oktober

2020

Accepted and

Presented

2

Finite Element Analysis of

New Artificial Hip Joint

Design

Departemen Teknik

Metalurgi dan Material,

Universitas Indoensia. 16-

17 Nopember 2020

Accepted and

Presented

3. Paten

No Judul Usulan Status Kemajuan

1 Desain Implan Tulang Pinggul Buatan Berbahan

Dasar Cobalt Chrome Molibdenum

Telah didaftarkan oleh

pihak LPPM ITS

4. Tesis

No Nama Mahasiswa NRP Judul Status

1 Fahny Ardian 02511950010004

Simulation of

Artificial Hip

Prosthesis Using

Finite Element

Analysis Under

Static and Dynamic

Loading

Sidang

Proposal

Thesis Bulan

Januari 2021

viii

Lampiran 2. Bukti Accepted dari International Meeting on Advances in Materials

(i-MAMM) 2020, Universitas Indonesia

ix

Lampiran 3. Bukti Accepted dari International Conference on Materials and Metallurgical

Engineering and Technology (ICOMMET) 2020, ITS

x

Lampiran 4. Bukti Sertifikat Presentasi di ICOMMET 2020 ITS Surabaya

xi

Lampiran 5. Draft HKI

Deskripsi

DESAIN IMPLAN TULANG PINGGUL BUATAN BERBAHAN DASAR COBALT CHROME

MOLIBDENUM

Bidang Teknik Invensi

Invensi ini berkaitan dengan metode proses pembuatan implan

tulang pinggul buatan cakupannya berupa penentuan desain implan

berbahan dasar Cobalt Chrome Molibdenum, sebagai media pembantu

rekonstruksi kerusakan tulang manusia baik akibat faktor usia,

kecelakaan, ataupun penyakit tertentu. Implan didesain memiliki

empat lubang di bagian stem dan rongga dibagian femoral head yang

berfungsi untuk menurunkan berat dari implan, mempercepat proses

penyembuhan dan dengan adanya lubang akan membuat tegangan yang

diterima oleh implan dapat tersebar merata sehingga akan

meningkatkan keamanan dan memperpanjang umur pakai dari implan

buatan.

Latar Belakang Invensi

Invensi ini telah dikenal dan digunakan untuk metode

penyembuhan pasien yang mengalami kerusakan pada tulang pinggul.

Tulang adalah organ dengan struktur kaku dan keras yang membentuk

kerangka manusia dan merupakan salah satu bagian dari tubuh manusia

yang sangat vital peranannya. Tulang memiliki beberapa fungsi

antara lain sebagai alat gerak pasif penopang tubuh, proteksi,

mendasari gerakan, homeostasis mineral (penyimpanan dan pelepasan)

dan memproduksi sel darah. Tulang manusia dapat mengalami beberapa

masalah seperti penurunan kekuatan (Osteoporosis), terkena penyakit

seperti kanker tulang dan arthritis, serta tulang manusia juga

dapat mengalami kehancuran karena kecelakaan atau benturan yang

keras. Untuk kasus-kasus tersebut maka alternatif pengobatan yang

diberikan kepada pasien adalah dengan menggantikan tulang buatan

xii

(bone replacement) yaitu pemasangan implan (implantation) pada

tubuh.

Pemilihan desain implan sangatlah penting khususnya pada

lokasi joint, seperti hip prosthesis joint (tulang pinggul), knee

joint (tulang lutut), shoulder joint (tulang bahu) dan spinal

(tulang belakang). Pada lokasi joint sangat membutuhkan desain

implan yang memiliki kekuatan (strength) dan ketahan gesek (wear

resistance) yang bagus sehingga akan meningkatkan keamanan dan umur

pakai dari implan buatan.

Selain itu desain implan tulang pinggul buatan juga sangat

berpengaruh terhadap hasil pemasangan implan tulang pinggul. Model

metal-on-metal (MoM) yaitu tanpa menggunakan semen tulang

(cementless) lebih cocok untuk diaplikasikan pada pasien berumur

muda yang memiliki mobilitas tinggi dalam aktivitas. Sedangkan

model MoM dengan menggunakan semen tulang lebih sesuai untuk pasien

usia lanjut, dimana aktivitas mobilitasnya tidak terlalu tinggi.

Model MoM dengan material yang sama (femur dan acetabular) dipilih

dengan alasan untuk mencegah korosi dalam tubuh menjadi parah.

Disamping itu, MoM juga dipilih sebagai pertimbangan untuk

menghindari munculnya partikel release dari acetabular yang

berbahan keramik atau polimer akibat gaya gesek. Desain geometri

juga sangat memegang peranan penting pada proses penyembuhan dan

kenyamanan pasien. Smart geometri sangat diperlukan untuk

mengurangi berat implan akibat kerapatan paduan pembuatnya, tanpa

mengabaikan sifat mekanik implan pada saat menerima beban.

Invensi teknologi yang berkaitan tentang desain implan tulang

pinggul sebelumnya juga telah diungkapkan sebagaimana terdapat pada

paten United States Nomor 81936 oleh Raymond G.Tronzo dengan judul:

Hip Prosthesis. Paten tersebut mengklaim bahwa bagian stem dan

bagian femoral head dibuat terpisah dan dapat disambungkan menjadi

satu bagian karena didalam stem dan femoral head miliki ulir. Pada

metode tersebut produk dari implan tulang pingggul dapat digunakan

oleh pasien dengan berbagai ukuran tulang pinggul dengan

mengkombinasikan ukuran stem dengan ukuran femoral head.

xiii

Invensi lainnya sebagaimana diungkapkan pada paten United

Stated. Nomor 271684 tanggal 15 Febuari 1952 oleh E.J. Haboush

dengan judul: Prosthesis for Hip Joint. Pada paten tersebut

diungkapka bahwa bagian femoral head dan stem yang dibuat menyatu

dan berbentuk meruncing dapat memperpanjang umur implan. Namun

invensi tersebut masih terdapat kekurangan yaitu mengenai massa

implan yang relatif berat karena terbuat dari logam

Namun dari beberapa invensi yang tersebut masih mempunyai

kelemehan dan keterbatasan yang antara lain adalah desain implan

memiliki massa yang relatif berat sehingga dapat memperlambat

penyembuhan proses penyembuhan dan juga dapat merusak tulang paha

(femur host) dan desain implan dari invensi diatas belum dilakukan

simulasi menggunakan komputer untuk mengetahui distribusi tegangan

selama pemakaiannya.

Selanjutnya Invensi yang diajukan ini dimaksudkan untuk

mengatasi permasalahan yang dikemukakan diatas dengan cara

menyediakan suatu desain implan tulang pinggul untuk menggantikan

tulang pinggul pasien yang rusak dengan cara melakukan desain ulang

dengan penambahan lubang pada stem dan pembuatan rongga di bagian

femoral head. Invensi yang diajukan ini mampu menghasilkan suatu

produk paduan implan tulang pinggul dengan berat 317,86 gram dengan

maksimal tegangan von misses sebesar 278,55 Mpa dengan safety factor

sebesar 1,8.

Uraian Singkat Invensi

Tujuan utama dari invensi ini adalah untuk mengatasi

permasalahan yang telah ada sebelumnya khususnya dalam hal

memperoleh desain implan tulang pinggul buatan yang memiliki massa

yang lebih ringan , umur pakai panjang dan kemampuan mekanik yang

baik. Invensi yang dilakukan adalah pada penambahan lubang

berbentuk bulat sejumlah 4 lubang di bagian stem dan membuat rongga

di bagian femoral head. Invensi ini bertujuan untuk menciptakan

implan dengan masa yang ringan namun memiliki kemampuan yang

maksimal dan umur pakai yang panjang.

xiv

Uraian Singkat Gambar

Gambar 1,adalah bentuk desain dari implan tulang pinggul tampak

depan

Gambar 2,adalah bentuk desain dari implan tulang pinggul tampak

samping kanan dan kiri

Gambar 3,adalah bentuk desain dari bagian femoral head

Ganbar 4,adalah distribusi tegangan (von misses) hasil simulasi

dari implan

Uraian Lengkap Invensi

Kerusakan pada tulang pinggul dapat diatasi dengan cara

pemasangan implan tulang pinggul buatan yang diharapkan dapat

merestorasi dan berfungsi secara normal. Invensi ini berisikan

tentang bentuk desain implan tulang pinggul.

Mengacu pada Gambar 1, yang memperlihatkan gambar detail

secara lengkap implan tulang pinggul yang terdiri dari bagian stem

menyatu dengan bagian femoral head. Mengacu pada Gambar 1,

menunjukkan bentuk, posisi dan jumlah lubang yang berada di stem.

Mengacu pada Gambar 2, memperlihat bahwa implan memeiliki bentuk

yang semakin kebawah semakin mengecil (tapered). Mengacu pada

Gambar 3 menunjukkan bentuk dari femoral head pada desain ini dibuat

rongga dengan tujuan untuk mengurangi berat dari implan. Pada Gambar

4 menunjukkan hasil distribusi tegangan pada implan tulang pinggul

buatan dari simulasi dengan software komputer

Dari uraian diatas jelas bahwa hasil dari invensi ini dapat

memberi manfaat bagi pasien penderita kerusakan atau gangguan pada

tulang pinggul karena secara praktis dan efisien akan mempercepat

penyembuhan pasca operasi dan akan memperpanjang umur pakai dari

implan tersebut dan invensi ini benar-benar menyajikan suatu

penyempurnaan yang sangat praktis khususnya pada desain implan

tulang pinggul buatan.

Hasil Simulasi yang telah dilakukan

Total Deformation : 14,715 mm

Equivalent Von Misses Stress

Maximum : 278,55 Mpa

xv

Minimum :0,049663 Mpa

Max. Principal Stress :232,57 Mpa

Max Equivalent elastic strain :0,01258 Mpa

Max principal elastic strain : 0,01008 Mpa

Safety Factor : 1,8

Metode Goodman :1,459627

Metde Soderberg :1,276533

Metode Gerber :1,804839

Berat Implan :317,86 gram

xvi

Klaim

1. Metode pembuatan implan tulang pinggul buatan berbahan dasar

Cobalt Chrome Molibdenum dengan desain implan seperti pada

gambar yang telah dilampirkan.

2. Metode pembuatan implan tulang pinggul buatan berbahan dasar

Coblat Chrome Molibdenum sesuai klaim 1 dapat menghasilkan produk

implan dengan berat 317,86 gram.

3. Metode pembuatan implan tulang pinggul buatan berbahan dasar

Cobalt Chrome Molibdenum sesuai klaim 2 akan menghasilkan safety

factor 1,8 dan maksimal distribusi tegangan yang dihasilkan

sebesar 278,55 Mpa

4. Metode pembuatan implan tulang pinggul buatan berbahan dasar

Cobalt Chrome Molibdenum sesuai klaim 3 akan menghasilkan total

deformation sebesar 14,715 mm.

xvii

Abstrak

DESAIN IMPLAN TULANG PINGGUL BUATAN BERBAHAN DASAR COBALT CHROME

MOLIBDENUM

Invensi ini berkaitan dengan proses pembuatan implan tulang

pinggul buatan cakupannya berupa penentuan desain implan, sebagai

media pembantu rekonstruksi distorsi tulang manusia baik akibat

faktor usia, kecelakaan, ataupun penyakit tertentu. Penentuan

desain implan dibuat memiliki lubang yang dapat menurunkan berat

dari implan, mempercepat proses penyembuhan dan dengan adanya

lubang akan membuat tegangan yang diterima oleh implan dapat

tersebar merata sehingga akan meningkatkan keamanan dan

memperpanjang umur pakai dari implan buatan. Obyek dari invensi ini

adalah untuk memperoleh desain implan tulang pinggul dengan

kemampuan mekanik yang baik dan memiliki umur pakai yang panjang.

Invensi yang dilakukan adalah pada penambahan lubang berbentuk

bulat sejumlah 4 lubang sepanjang bagian femoral dan pada bagian

femoral head yang memiliki rongga. Invensi ini bertujuan untuk

menciptakan implan dengan masa yang ringan namun memiliki kemampuan

yang maksimal.

xviii

Gambar. 1

Gambar. 2

xix

Gambar. 3

Gambar. 4

xx

Lampiran 6. Draft Paper Untuk ICOMMET 2020 ITS Surabaya

Finite Element Analysis of New Design Artificial Hip

Prosthesis

Fahny Ardian1, a), Yuli Setiyorini1, b), Sungging Pintowantoro1,c), Mas Irfan P. Hidayat1,d), Anni Rahmat 2,e)

1Material Engieering Department, Sepuluh Nopember Institute of Technology, Surabaya, East Java, Indonesia 2 Chemical Engineering Department, Semen Indonesia International University, Gresik, East Java, Indonesia

Corresponding author: a)fahny1923@gmail.com b) yuli_setyorini@mat-eng.its.ac.id c) sungging@mat-eng.its.ac.id d) irfan@mat-eng.its.ac.id

e) ar_298@yahoo.com

Abstract. Bone is an organ with solid and hard structures that form the human skeleton and is a part of the human body that

is vital in its role. Human bones have several problems such as decreased strength (Osteoporosis), contracting diseases such

as bone cancer and arthritis, and human bones can fracture due to accidents or harsh impacts. For these cases, the alternative

treatment given to patients is an artificial bone replacement. The choice of implant material is very important especially at

the location of the joint, such as the hip prosthesis joint (hip bone). At the joint location, it needs materials that have good

strength and wear resistance. Besides that, the design of the hip prosthesis joint implant is also very influenced by the patient's

treatment results. A metal-on-metal (MoM) model that is without the use of bone cement (cementless) is more suitable for

application in young patients who have high mobility in activity. The MoM model with the same material was chosen with

the reason to prevent corrosion in the body cause environmental effect. Geometries design also plays an important role in

the healing process and patient comfort. Forces applied to the implant due to human activity generates several forces and

failed implant material. Therefore, it is important to ensure the hip prostheses against static force. In this study, five Artificial

Hip Prosthesis (AHP) designs with varying thickness and number of holes for hip prosthesis were modeled. Static behavior

and responses of these AHP designs were analyzed using ANSYS 19.1. Static analyses were conducted under body load.

SolidWorks 2014 was used for CAD modeling of the AHP designs. The performance of the new AHP designs was

investigated for CoCrMo and SS 316 L materials and compared to each other. The design objective for AHP design is to

have a low equivalent von misses stress (safety factor) and displacement. Based on the static analysis result, the safety factor

for the fatigue life of the implant design has been calculated based on Goodman, Soderberg, and Gerber fatigue theories. The

result shows that Design made of CoCrMo is better than SS 316 L

Keyword(s): Artificial Hip Prosthesis, Biocampatibilty, Finite Element Analysis, Bone, Design

INTRODUCTION

Biomaterial is a synthetic material which used to replace or restore function to a body tissue and is continuously

or intermittently in contact with body fluids [1][2]. Biomaterials can used to replace the lost or fracture bone. A

biomaterial can exhibit specific interaction with cell that will lead to stereotyped or natural response. One of the most

successful techniques in replacement of deterioration joint function is artificial hip joint replacement. The total hip

prosthesis procedures have recently become the most successful orthopedic surgery procedures. Artificial hip prosthesis

(AHP) is being implemented in large numbers worldwide. AHP is performed because of osteoarthritis, bone cancer and

fracture in the hip joint [3]. The strain, stress, deformation, amount of wear safety factor, and fatigue may dictate how

the implant is performing. Although AHP surgeries have been very successful in recent years, roughly 10% fail within

10 years [4]. The 10% failure rate is due to many reasons, with the most important reasons being: dislocation of the ball

in the liner or bone cement not adhering to the hip stem. A fulcrum system is believed to be the mechanism by which

the ball section is forced out of the cup/liner section. A reduction surgery manipulates the head back into the liner. The

xxi

design of a hip implant involves many parameters, which include stem length, cross-section, neck length, neck angle,

and ball diameter [5].

Artificial hip joint replacement is the installation of artificial implants (hip joint) to replace damaged hip bones.

AHP must be able to stick to and form a network with the human body to be able to produce good implant function.

Failures that occur in implants can be dangerous and cause pain for patients. Failures experienced by AHP can be caused

by 2 main factors namely mechanical and chemical [6]. Now there are two methods in the installation of implants

namely cemented and cementless. The cemented hip joint method requires additional cement as a medium to attach the

hip joint to the femur bone. With the addition of this cement will increase the possibility for the formation of debris

produced by the cement due to chemical and mechanical processes. Whereas the cementless method does not require

cement to attach. In this method, AHP is expected to be directly integrated with femur bone. Both of the above methods

together require certain criteria in AHP designs in order to produce the best function. Among other things have the right

dimensions and sizes according to the patient, has a relatively light weight, has good mechanical properties and good

corrosion resistant [7][8].

The hip joint is a joint between femur and acetabulum of pelvis. The main function of hip joint is to support

the weight of the human body in daily activities [6]. Failures of hip prosthesis have been reported due to fatigue failure

of hip joint stem, fracture of bone cement and wear caused by sliding present between head and socket. In other word

fatigue fracture and wear are the basic mechanisms associated with failure of hip prosthesis [9][10]. This analysis was

an attempt to analyze five new AHP designs in use as an implant that have been modified with an effort to reduce

weight, stress and displacement and increase osseintegration. The analysis was performed using ANSYS 19.1, a FEA

package. The AHP designs were analyzed with the forces and momen inertia. The results from the FEA were compared

with the other AHP designs. The design objective for a hip stem is to have a low stress, displacement, and safety factor

at a very high fatigue life. Fatigue and stress analyses were performed assuming that the implants were made of metal

and metal [6][11].

Several studies have been carried out on artificial hip joint to determine lifetime and safety factor and its

reaction to static loading. This artificial hip prosthesis is designed to be able to replace the function of the hip bone,

therefore this AHP must be able to withstand both static and dynamic loads that present human daily activities such as

standing, sitting walking, etc. To find out whether this AHP design can be able to withstand static or dynamic loads, a

modeling simulation can be done using computer software. The ability and success of AHP installation using the

cementless method is very dependent on the geometry and material selection of the implant. Because the cementless

method does not use cement as an adhesive, it requires the geometry of a very precise implant with the patient's femur

bone. Besides that, it is needed a material that has high mechanical properties with a light weight and has a good

biocompitibilty and mechanical properties [12][13][14]. In general, AHP is only able to withstand burdens for 5-10

years so with the new design it is expected to be able to withstand the burden for at least 20 years [16]. In this study

variations in the design of the geometry and thickness were carried out in addition to the variations in the constituent

materials. To design AHP using SolidWorks 2014 software. To simulate static loading on new designs using ANSYS

19.1 software. To find out and calculate the stress distribution and safety factor of the AHP design using ANSYS

software. Common materials used for hip implants include stainless steel (SS) and cobalt chrome alloys (CoCrMo).

These materials are used because they have high strength to weight ratio and also have an excellent biocompatibility

based upon longterm usage in humans. One of the problems of a hip implant is that the material does not have the same

composition, strength and characteristics as that of a bone. The stress distribution, safety factor and displacement on

each of the AHP designs were generated from force about 3000 N and moment inertia 68,5 Nm acting on the ball

[2][3][17].

In many literature, stress distribution and fatigue failures of prosthesis have been analyzed separately [18].

This paper investigates the dependence of one failure mode over the other mode. Therefore, it is essential to analyze

the stress distribution and fatigue failures simultaneously or sequentially, which is the aim of present research. To

estimate the failures of the prosthesis, finite element analysis has been used. This method is widely used as a time saving

and cost efficient computing method in biomedical engineering [19][20].

METHODOLOGY

In this paper an attempt has been done to consider safety effects sequentially to estimate the useful life of the

prosthesis. First, a finite element model of the hip joint prosthesis was developed in SolidWorks 2014 shown in Figure

1. The developed model was imported in ANSYS 19.1 for analysis. Static structural analysis was performed applying

average human body weight and equivalent stress (Von Misses) distribution was calculated. Stress variation with respect

to time was recorded. Stress variation with respect to time was recorded and the results were used to determine safety

of the prosthesis. The aim of a novel design for a new AHP design was obtained good, reliable, lights and durable

design of AHP. The purpose of making this new design is to get an AHP design with the ability to have the maximum

capability with the lightest weight. The shape of AHP great influenced the ability of AHP [21][22]. AHP design must

reduce the stress concentration during loading and will increase the lifetime of the AHP. With the addition of holes in

xxii

the AHP is expected to reduce the weight of the AHP and the addition of these holes will be able to distribute the stress

evenly and increase osseointegration process shown in Table 1-2.

FIGURE 1. New Artificial Hip Prosthesis Design

Tabel 1. Research Parameters for CoCrMo

Material Number of Hole Thickness (mm)

CoCrMo

0

12

1

2

3

4

0

13

1

2

3

4

0

14

1

2

3

4

0

15

1

2

3

4

xxiii

Tabel. 2 Research Parameter for SS 316 L

Material Number of Hole Thickness (mm)

SS 316 L

0

12

1

2

3

4

0

13

1

2

3

4

0

14

1

2

3

4

0

15

1

2

3

4

FINITE ELEMENT ANALYSIS

Finite element model required for finite element analysis was created by discretizing the geometric (CAD)

model shown in Figure 2 into smaller and simpler element. The FEM model of prosthesis consist of total 820652 nodes

and 581146. The finite element models of the stem shapes and the bone are shown in Figure.3. The physical interactions

at femur bone and stem interface during loading were taken into account through bonded surface to surface contact

features of ANSYS 19.1. Two different materials, CoCrMo and SS 316 L, for implant were used for the finite element

analyses. Behaviour of these materials are represented with linear isotropic material model. Mechanical properties of

CoCrMo and SS 316 L are shown in Table 3.

FIGURE 2. Assembly of AHP and Femur Bone

Static analyses of prosthesis should be conducted to ensure about the safety of the design. In the literature,

prosthesis is often designed according to the result of static analysis. Static finite elemen analysis is mostly conducted

under body weight loads. Static loading to the prosthesis which must be taken into account not to cause fracture of

fatigue failure of the prosthesis. To investigate how static analysis result differ from each other, prosthesis were analysed

under static body weight load [23].

xxiv

FIGURE 3. Finite Element Model of Artificial Hip Prosthesis

For static analysis, a load of 3000 N (F Static) with an angle of 20o and moment inertia 68,5 Nm is applied on the

surface of the implant bearing as shown in Figure 3. Static load represents a person of 76 kg. An abductor muscle load

of 1250 N (F Abductor muscle) was applied at an angle of 20o to the proximal area of the greater trochanter. An ilio tibial

tract load of 250 N (F Iliotibial-tract) is applied to the bottom of the femur in the longitudional femur direction. Distal end

of the femur was constrained not to move in horizontal direction [24].

Tabel. 3 Mechanical Properties [12]

Materials Young’s Moudulus (GPa) Possion Ratio Yield Strength

Femur Bone 16,2 0,36 135

SS 316 L 193 0,3 170

CoCrMo (as cast) 210 0,3 448-517

RESULT AND DISCUSSION

Finite element analyses of the prosthesis are carried out using ANSYS 19.1. It is important that the maximum

equivalent stress on the prostheses should be lower than the yield strength of the prosthesis materials for safety. In the

static structural analysis, stresses were always lower than the respective material strengths. Maximum Von Misses

stresses in the AHP designs resulted from static finite element analyses are shown in Figure 4-7. It is important that the

maximum equivalent stress on the prosthesis should be lower than the endurance limit of the prosthesis materials for

safety. The calculated Von Misses stress as shown in table are much lower than yield stress of CoCrMo and SS 316 L

given in Table 4-5. This mean in AHP made of SS 316 L is unsafe because the maximum von misses stress in above

the yield point of SS 316 L. In other hand AHP made of CoCrMo several of them is safe during static loading. Design

with 15 thickness and 1 hole made of CoCrMo is the best design for under static loading.

xxv

Tabel 4. Maximum Von Mises Stress of AHP made from SS 316L under static loading

Tabel 5. Maximum Von Mises Stress of AHP made from SS CoCrMo under static loading

Material Thickness Number of Hole

Maximum

Von Misses

Stress (MPa)

Yield

Strength

(MPa)

SS 316 L

12

0 490,71

170

1 514,61

2 499,76

3 495,01

4 495,55

13

0 399,29

1 402,05

2 409,68

3 399,77

4 403,41

14

0 324,67

1 320,92

2 319,18

3 319,04

4 317,66

15

0 279,08

1 271,77

2 329,2

3 469,57

4 308,44

Material Thickness Number of

Hole

Maximum

Von Misses

Stress (MPa)

Yield

Strength

(MPa)

CoCrMo

12

0 490,69

448

1 514,82

2 499,8

3 495,2

4 495,74

13

0 399,38

1 402,2

2 416,18

3 400,02

4 403,67

14

0 324,81

1 321,18

2 296,5

3 319,16

4 317,81

15

0 279,23

1 272,07

2 337,18

3 482,14

4 314,04

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FIGURE.4 Von Mises Stress distribution under static loading for CoCrMo material ( 4 holes )

FIGURE. 6 Von Mises Stress distribution under static loading for CoCrMo material ( Thickness: 15 mm )

xxvii

FIGURE. 7 Von Mises Stress distribution under static loading for SS 316 L material ( Thickness: 15 mm )

FATIGUE ANALYSIS

An excellent implant design should satisfy maximum or an infinite fatigue life. This can only be ensured by

physical testing or a fatigue analysis. In this study, fatigue life of the prosthesis upon finite element stress analysis is

predicted using the computer code of ANSYS Workbench. Fatigue calculations of the implant are conducted for

CoCrMo and SS 316 L materials. In fatigue calculations, fatigue material models shown in Figure 8 are used. Figure

8 known as S–N curves shows fatigue properties of CoCrMo alloy in terms alternating stress versus number of cycles.

Fatigue life of implant was determined based on Goodman, Soderberg, Gerber and mean stress fatigue theories. Stress

life (S/N) approach was used for calculated the fatigue life of the implant. This formula is useful for the initial process

of materials selection of implant that will be subjected to high cyclic loading conditions. The advantage of this approach

FIGURE.5 Von Mises Stress distribution under static loading for SS 316 L material ( 4 holes )

xxviii

is that it represents both initiation and propagation of cracks in the aggressive environment. In the finite element model,

the materials (bone, metal and cement) are considered to be elastic and the analysis was performed according to infinite

life criteria (109 cycles). Therefore, the maximal stress distribution was ensured to be lower than the lowest stress on

the S/N curve [18]. In Table 6, N indicates safety factor for fatigue life in loading cycle, Se for endurance limit and Su

for ultimate tensile strength of the material. Mean stress 𝜎𝑚 and alternating stress 𝜎𝑎 are defined, respectively, as

𝝈𝒎 =(𝝈𝒎𝒂𝒙+𝝈𝒎𝒊𝒏)

𝟐 (1)

𝝈𝒂 =(𝝈𝒎𝒂𝒙− 𝝈𝒎𝒊𝒏)

𝟐 (2)

Tabel 6. Fatigue analyses were performed according to Goodman, Soderberg and Gerber methodes [18]

Fatigue Theories Formulas

Goodman (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑢

) =1

𝑁

Soderberg (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑦

) =1

𝑁

Gerber (𝑁. 𝜎𝑎

𝑆𝑒

) + (𝑁. 𝜎𝑚

𝑆𝑢

)2

= 1

FIGURE. 8 Fatigue Curve (S-N curve) for CoCrMo [18]

Tabel 7. Minimum Safety Factor of AHP design for CoCrMo material under static loading Material Thickness Number of Hole Goodman Soderberg Gerber

CoCrMo

12

0 0,828562 0,724638 1,024513

1 0,78972 0,69067 0,976483

2 0,813461 0,71143 1,005842

3 0,821013 0,718037 1,015179

4 0,82012 0,717255 1,014075

13

0 1,017994 0,89031 1,258745

1 1,010865 0,884072 1,249934

2 0,976896 0,854369 1,207926

3 1,016372 0,888889 1,256741

4 1,007174 0,880848 1,245365

14

0 1,251709 1,09471 1,547733

1 1,265883 1,107095 1,56527

2 1,273335 1,113613 1,574484

3 1,273884 1,114097 1,575158

4 1,279282 1,118823 1,581829

15

0 1,456047 1,273412 1,800402

1 1,494368 1,306925 1,847788

2 1,20579 1,05455 1,490956

3 0,843249 0,737485 1,042671

4 1,294648 1,132258 1,600831

xxix

Tabel 8. Minimum Safety Factor of AHP design for SS 316 L material under static loading Material Thickness Number of Hole Goodman Soderberg Gerber

SS 316 L

12

0 0,70836 0,413746 0,875884

1 0,675456 0,394532 0,835196

2 0,695534 0,406253 0,860025

3 0,702205 0,410152 0,868272

4 0,70144 0,409705 0,867328

13

0 0,870542 0,508476 1,076421

1 0,864574 0,504983 1,069044

2 0,848461 0,495581 1,049117

3 0,869503 0,507864 1,075138

4 0,86165 0,503284 1,065425

14

0 1,070625 0,62534 1,323823

1 1,083159 0,63264 1,33933

2 1,089062 0,636089 1,34663

3 1,089531 0,636371 1,347206

4 1,094254 0,639139 1,353042

15

0 1,245534 0,72749 1,540102

1 1,279038 0,747057 1,581532

2 1,055895 0,616734 1,305612

3 0,740245 0,432374 0,915308

4 1,126972 0,658242 1,393501

From Table 7-8, we can see that all new AHP design has different safety factor values according to all fatigue

criteria. This means that several AHP designs are bad design and may fail under static loading is considered. Among

new AHP design, AHP design with 15 mm thickness and 1 hole made from CoCrMo better than the others in fatigue

life. Because this design has higher safety factor value in all faigue theories. The displacement value of assembly AHP

and femur bone are given in Table 9-10.

Table 9. Maximum deformation of assembly AHP and Femur Bone (CoCrMo) Material Thickness Number of Hole Total Deformation (mm)

CoCrMo

12

0 13,914

1 13,848

2 13,77

3 13,706

4 13,658

13

0 14,149

1 14,068

2 14,007

3 13,952

4 13,908

14

0 14,228

1 14,156

2 14,092

3 14,04

4 13,996

15

0 14,075

1 13,99

2 13,919

3 13,855

4 13,812

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Table 10. Maximum deformation of assembly AHP and Femur Bone (SS 316 L)

CONCLUSION

The aim of this study was to determine the fatigue endurance of cementless implant. In this study, 20 different

new AHP design for hip prosthesis are designed. AHP design have varying thickness geometry and varying number of

holes. First new AHP design has standard geometry without hole. The other AHP design has hole with varity number

on the stem. The number of hole and varying thickness are designed to reduce weight of the implant and to stick the

implant to the femur bone securely also increase osseointeration process. Static FE analyses of AHP have been

conducted using ANSYS 19.1. Based on static FE analysis results, safety factors for fatigue life have been calculated.

Fatigue calculations have been carried out for CoCrMo and SS 316 L materials based on Goodman, Soderberg, and

Gerber fatigue theories. All calculations are performed according to the infinite fatigue life criteria. Finite element

analyses in this study show that several new AHP designs are safe against fatigue failure. The best AHP design for

fatigue under static loading is new AHP design with 15 mm thickness and 1 hole made of CoCrMO material. Considered

the weight of the shock absorber we recommended design of implant with 14 mm thickness and 4 holes made of

CoCrMo. The new AHP design made of SS 316 L is not recommended for Artificial Hip Prosthesis because in FEA

predicted to be unsafe under static loading.

ACKNOWLEDGMENTS

This research was supported by internal funding from the Sepuluh Nopember Institut of Technology

REFERENCES

[1] Kazim Tur. Biomaterials and Tissue Engineering for Regenerative repair of Articular Defect. Departemen of

Materials Engineering, Atilim University,Ankara, Turkey. (2009)

[2] Hasirci, Vasif. Fundamentals of Biomaterials, Springer Science. New York (2018)

[3] Park, John and Lakes. Biomaterials in Introduction. Third edition. Vol 1.USA CRC Press (2007)

[4] Habiba Bougherara, Rad Zdero. A biomechanical assessment of modular and monoblock revision hip implants

using FE analysis and strain gage measurement. Department of Mechanical and Industrial Engineering, Ryerson

University, Toronto, ON, M5B-2K3, Canada (2010)

[5] X Li, D Li. The effect of stem structure on stress distribution of a custom-made hip prosthesis. State Key Lab for

manufacturing system engineering, Xi’an Jiaotong University, Xi’an, ShaanXi, China (2009)

[6] Joseph C. McCarthy. Hip Joint Restoration. Springer Science+Business LLC, New York (2017)

[7] Buddy D, Ratner. Biomaterials Science an Introduction to Materials in Medicine. Third Edition, Elsevier Science

and Sabre Foundation Book. (2013)

Material Thickness Number of Hole Total Deformation

SS 316 L

12

0 14,11

1 13,882

2 13,805

3 13,74

4 13,692

13

0 14,177

1 14,097

2 14,037

3 13,981

4 13,938

14

0 14,254

1 14,182

2 14,118

3 14,066

4 14,028

15

0 14,097

1 14,013

2 13,942

3 13,879

4 13,812

xxxi

[8] Tighe T, Brazil D. Metallic Modular Taper Junctions in Total Hip Arthroplasty. Joint Implant Surgery & Research

Foundation, Chargin Falls, OH 44022 US (2015)

[9] El-Din Hussam, El-Sheikh. Finite element simulation of hip joint replacement under static and dynamic loading.

School of Mechanical and Manufacturing Engineering Dublin City University. (2002)

[10] K. Colic, A.Sedmak. The current approach to research and design of the artificial hip prosthesis: a review.

University of Belgrade, Innovation Center, Faculty of Mechanical Engineering, Kraljice Marije 16, 11 000

Belgrade, Serbia (2016)

[11] David Bennet, Tarun Goswami. Finite Element Analysis of Hip Stem Design. Department of Mechanical

Engineering, Ohio Northern University, Ada, OH 45810, United States

[12] Murphy Williams. Handbook of Biomaterials Properties. Springer Science+Business LLC, New York (2016)

[13] Rafiq Mohammed. Computational Biomechanics of the Hip Joint. Springer Science + Business LCC, New York.

(2014)

[14] K. Mohan Iyer. The Hip Joint Adult Advances and Development. Pan Standford Publishing Pte. Ltd Singapore.

(2018)

[15] Morrey F. Bernard. Joint Replacement Arthroplasty Basic Science, Hip, Knee and Ankle Fourth Centennial

Edition, Lippin Cott Williams and Wilkins, Philadelphia, PA 19103 USA (2011)

[16] M Schaldach, D. Hohmann. Advance in Artificial Hip and Knee Joint Technology. Springer-Verlag Berlin

Heidelberg, New York (1976)

[17] Xiaolin. Finite Element Modelling and Simulation with ANSYS Workbench. CRC Press, London. (2019)

[18] Oguz Kayabasi, Fehmi Erzincanli. Finite Modelling and Analysis of a New Cemented Hip Prosthesis. Department

of Design and Manufacturing Engineering, Gebze Institute of Technology, PK. 141, 41400 Gebze, Kocaeli,

Turkey (2005)

[19] Jui-Pin Hung, James. A Comparative Study on Wear Behaviour of Hip Prosthesis by Finite Element Simulation.

Institute of Mechanical Engineering, National Chung-Hsing University, Taichung, Taiwan. (2002)

[20] Nithin Kumar Kc, Tushar Tandon. Biomechanical Stress Analysis of a Human Femur Bone Using ANSYS.

Department of Mechanical Engineering, Graphic Era-University, Dehradun, Uttarakhand, India (2015)

[21] C. Desai, H. Hirani, A. Chawla. Life Estimation of Hip Joint Prosthesis. Departmen of Mechanical Engineering,

IIT Delhi, New Delhi 110016, India. (2014)

[22] Brian P. McNamara. Relationship Between Bone – Prosthesis Bonding and Load Transfer in Total Hip

Reconstruction. Biomaterials Technology Laboratory, Rizzoli Orthopaedic Institute, Bologna, Italy. (1997)

[23] Rogerz, Kara. Bone and Muscle Structure, Force and Motion. Britannica Educational Publishing. New York.

(2011)

[24] David. Finite Element Analysis of Hip Stem Design. Departemen of Mechanical Engineering. Ohio Nortehn

University.United States. (2008)

xxxii

Lampiran 7. Draft Paper Untuk i-MAM 2020 Universitas Indonesia

Finite Element Analysis of New Artificial Hip

Joint Design

Yuli Setiyorini1.a), Sungging Pintowantoro1.b), Mas Irfan P. Hidayat1.c) Fahny Ardian1.d), Anni Rahmat2.e)

1Material Department, Sepuluh Nopember Institute of Technology, Surabaya, East Java, Indonesia 60111 2 Chemical Engineering Department, Semen Indonesia International University, Gresik, East Java, Indonesia

Corresponding author: a) yuli_setyorini@mat-eng.its.ac.id b) sungging@mat-eng.its.ac.id

c) irfan@mat-eng.its.ac.id d) fahny1923@gmail.com e) ar_298@yahoo.com

Abstract. Bone is an important part of the human’s body. Trauma is a main cause of the death and

disability. The most successful treatment to overcome the traumas is Total Hip Replacement (THR).

The use of metallic on metallic (MoM) artificial hip joint have advantages and disadvantages for use

in THR. The geometries, shape and number of holes have been intended to reduce the weight of

implant and increase the osseointegration process. In this study a finite element analysis (FEA) was

conducted on the new design of implant. In this study nine different new implant design for THR have

been designed to evaluate an optimum implant design. The implant design has geometries and varying

shape and number of holes. The implant design was analyzed at force 3000 N and moment inertia

68,5 N.m. Femur bone and implant were modelled using SolidWorks 2014 and analysis using ANSYS

19.1. Based on static analysis result, safety factor for fatigue life of the implant design have been

calculated. Safety factor calculation have been carried for CoCrMo and Ti-6Al -4V alloy based on

Goodman, Soderberg and Gerber fatigue theories. The result show that Design 1 made of Ti-6Al-4V

is better than CoCrMo.

Keywords: Finite Element Analysis, Design, Biomaterials, Hip Joint, Fatigue

INTRODUCTION

The number of total hip replacement operations being performed is increasing year by year, and it is estimated

that, worldwide, there are more than 1 million patients needing a total hip replacement operation every year [1].

However, the standard hip prosthesis currently adopted in clinical replacement operations cannot be perfectly suited to

every patient’s personal characteristics. Although more effort has been made to satisfy the patients’ individual needs,

for example by increasing the range of sizes and types of hip prosthesis, a large proportion of total hip arthroplasties

(THAs) become loose after they have been implanted for decades. Consequently, approximately 30 per cent of patients

who have undergone total hip replacement need revision operations. Recent studies show that the failure of the THA is

often attributed to infection and aseptic loosening and that the latter is the primary factor in long-term loosening. Stress

distribution on the prosthesis is a significant factor influencing the aseptic loosening. Thus, a custom-made hip is

xxxiii

essential to achieve the initial stability and hence longevity which result from an optimal stress distribution. Although

the relationship between the structure and stress at the fixation site and the bearing surface has been analysed, guidelines

on the design of custom-made hip prostheses have not yet been established. The four principal causes of aseptic

loosening are: mechanical failure of the implant or cement; introduction of wear debris into the interface region; relative

motion across the interface; and stress shielding in the bone. The cross-section of the femoral stem has a great influence

on the performance of a prosthesis since it enhances load transfer from the implant to the bone [2][3]. In addition, cross-

sections that precisely fit and restore the individual hip geometry can reduce stress at the cement–implant and cement–

femur interfaces and improve the functional performance and longevity of the THA [4][5].

Finite element analysis (FEA) is the process of simulating the behaviour and phenomena of a structural

engineering under given conditions so that it can be assessed using the finite element method (FEM). FEA is used by

engineers to help simulate physical phenomena and thereby reduce the need for physical prototypes, while allowing for

the optimisation of components as part of the design process of a project. FEA applying mathematical models to

understand and evaluated the effects of real-world conditions on a structural engineering. These simulations, which are

conducted via specialised software, allow engineers to locate potential problems in a design, including areas of tension

and weak spots. With the use of mathematics. It is possible to understand and quantify structural or fluid behaviour,

wave propagation, thermal transport and other phenomena [6][7][8].

The main function of the hip joint is to support the body so that it remains strong during daily activities.

Failures of artificisl hip prosthesis have been reported due to fatigue failure of hip joint stem, fracture of bone cement

and wear caused by sliding present between head and socket. In other word fatigue fracture and wear are the basic

mechanisms associated with failure of hip prosthesis. This analysis was an attempt to analyze five new AHP designs in

use as an implant that have been modified with an effort to reduce weight, stress and displacement and increase

osseintegration. The analysis was performed using ANSYS 19.1, a FEA package. The AHP designs were analyzed with

the forces and momen inertia. The results from the FEA were compared with the other AHP designs. The design

objective for a hip stem is to have a low stress, displacement, and safety factor at a very high fatigue life. Fatigue and

stress analyses were performed assuming that the implants were made of metal and metal.

METHODOLOGY

Shape of implant have prominent influence on the performance of implant during treatment period. The design

of prostheses must appropriate to the structure of patient’s femur, collodiaphyseal angle, outline of medullary cavity,

length of the femur and gait [9]. In this research a series of prostheses design with different shape and amount of hole

in stem shown in Figure 1-2. Stem with different shape and amount of hole generally reduce stress concentration and

stress distribution and perhaps to increase lifetime and safety factor of the prosthesis. Prosthesis without hole provide

maximal stress distribution. However, it increased the weight of implant and increase the possibility of failure in femur

host caused by stress sliding. In other hand, prosthesis with several holes will decrease the weight of implant and the

possibility of failure in femur host caused by stress sliding. Nevertheles prosthesis with several hole lead to high stress

concentration [10][11]. Therefore, this research needs to be done in order to obtain an optimal prosthesis design in terms

of weight, healing period and good mechanical properties. In this study, nine different prosthesis design with varying

shep and amount of hole are generated to achieve both good healing process and mechanical properties. The research

parameters of this research can be seen in Table 1.

Figure 1. New Artificial Hip Prosthesis Design

xxxiv

Figure 2. All Model of Hip Prosthesis Design

Table 1. Research Parameters

FINITE ELEMENT ANALYSIS

ANSYS, a computer based finite element package, was used in order to perform the finite element and

optimization analyses. The design optimization in the ANSYS package is a powerful tool that can be used in either of

the two ways [6]. The geometry can be optimized by two different methods. The two methods are topological

optimization and using the module that is preprogrammed into ANSYS. The topological approach uses a form shape

optimization. A topological optimization determines the best use of a material using the criteria specified by the user

(i.e., global stiffness, natural frequency, etc.). For the purpose of this analysis, the module in ANSYS was used because

an optimization of the geometry parameters (dimensions) was desired, not a change in the shape that was being

determined from the topological method.

Material Variabel

CoCrMo

Desain 1

Desain 2

Desain 3

Desain 4

Desain 5

Desain 6

Desain 7

Desain 8

Desain 9

Ti-6Al-4V

Desain 1

Desain 2

Desain 3

Desain 4

Desain 5

Desain 6

Desain 7

Desain 8

Desain 9

xxxv

Finite element model of the prostheses was generated in SolidWorks 2014. The prostheses model was imported

in ANSYS 19.1 for analysis using Parasolid file extension. Static structural analysis was carried out applying average

human body weight and rersponse and behaviour of prostheses was calculated. Finite element model required for finite

element analysis was created by discretizing the geometric (CAD) model shown in Figure 3 into smaller and simpler

element. The FEM model of prosthesis consist of total 820652 nodes and 581146. The finite element models of the

stem shapes and the bone are shown in Figure 4. The fixation methods used between the implant and the bone can be

categorized into the following four categories: press fit or frictional fit implants; adhered implants; cemented implants

and ingrown implants.

The fixation system used determines how the hip stem will secure and/or adhere to the femur bone. The

physical interactions at femur bone and stem interface during loading were taken into account through bonded surface

to surface contact features of ANSYS 19.1. To build the finite element model, femur and implant were meshed using a

higher order three-dimensional solid element SOLID187. SOLID187 element is a higher order 3-D, 10-node element.

SOLID187 has a quadratic displacement behavior and is well suited to modeling irregular meshes (such as those

produced from various CAD/CAM systems). The element is defined by 10 nodes having three degrees of freedom at

each node: translations in the nodal x, y, and z directions. For modeling the contact between femur and implant interface

and the CONTA174 elements was used. CONTA174 element was located on the surfaces of 3-D solid element

SOLID187. CONTA174 has the same geometric characteristics as the solid element face with which it is connected.

Contact occurs when the element surface penetrates one of the target segment elements (TARGE170) on a specified

target surface. Fine mesh was applied to the implant models [7][11]

Two different materials, CoCrMo and Ti-6Al-4V, for implant were used for the finite element analyses.

Behaviour of these materials are represented with linear isotropic material model. Materials properties of CoCrMo and

Ti-6Al-4V shown in Table 2. Static structural analyses of prosthesis should be conducted to ensure about the properness

of the design. In the literature, prosthesis is often designed according to the result of static structural analysis. Static

loading to the prosthesis which must be taken into account not to cause fracture of fatigue failure of the

prosthesis[12][13][14].

Figure 3. Assembly of AHP and Femur Bone

xxxvi

Figure 4. Finite Element Model of Artificial Hip Prosthesis

The boundary condition according to the patient’s personal characteristics were loaded into the finite element model.

In the static analysis a load of 3000 N (five times the patiens’s body) with an abduct angle of 90 o was applied on the

surface of femoral head. An abductor muscle load of 1250 was applied at an angle of 20 o to the proximal area of the

greater trochanter. The distal end of the femur was fully restrained against displacement in all direction. Moment inertia

about 68,5 Nm was applied on the surface of implant bearing. An ilio tibial tract load of 250 N (F Iliotibial-tract) is applied

to the bottom of the femur in the longitudional femur direction. Distal end of the femur was constrained not to move in

horizontal direction [15][16]

Tabel 2. Materials Properties

Material Young’s Moudulus

(GPa) Possion Ratio

Yield Strength

(MPa)

UTS

Femur Bone 16,2 0,36 135 -

Ti-6Al-4V 110 0,32 830 655

CoCrMo (as

cast) 210 0,3 448-517

960 - 1270

RESULT AND DISCUSSION

Finite element analyses of the prosthesis are carried out using ANSYS 19.1. The rules of optimization in this

study are to ensure that, for safety, the maximum equivalent stress on the prosthesis should be lower than the endurance

limit of the prosthesis materials. In addition, the stress on the prosthesis design should be evenly distributed. The von

Mises stress was adopted as the criterion in this work. The von Mises yield criterion is part of a plasticity theory that

applies best to ductile materials, such as metals. Prior to yield, the material response is assumed to be elastic. In materials

science and engineering the von Mises yield criterion can be formulated in terms of the von Mises stress. The von Mises

stress is used to predict yielding of materials under any loading condition from results of simple uniaxial tensile tests.

The von Mises stress has therefore also been widely used in the finite element analysis of artificial joints. Figure 5

shows the von Mises stress on the prosthesis design made of CoCrMo under static loading. Figures 6 show the von

Mises stress on the prosthesis design made of Ti-6Al-4V under static loading. The calculated Von Misses stress as

shown in table are much lower than yield stress of CoCrMo and Ti-6Al-4V shown in Table 3. This mean in prosthesis

design made of Ti-6Al-4V is safe because the maximum von misses stress is lower than the yield point of Ti-6Al-4V.

In other hand AHP made of CoCrMo several of them is unsafe during static loading (Design 7 & 8). Design 1, without

hole made of Ti-6Al-4V is the best design for under static loading.

xxxvii

Table 3. Maximum Von Mises Stress of AHP under static loading

FIGURE.5 Von Mises Stress distribution under static loading for CoCrMo material

Material Variabel Maximum Stress

(MPa)

Minimum Stress

(MPa)

Yield Strength

(MPa)

CoCrMo

Desain 1 240,72 0,047342

448

Desain 2 244,52 0,06563

Desain 3 337,17 0,03361

Desain 4 421,44 0,056562

Desain 5 433,35 0,049118

Desain 6 349,23 0,05388

Desain 7 519,37 0,033695

Desain 8 583,32 0,047423

Desain 9 437,49 0,060932

Ti-6Al-4V

Desain 1 240,64 0,047344

830

Desain 2 244,43 0,071267

Desain 3 269,76 0,035496

Desain 4 334,15 0,04797

Desain 5 360,87 0,062188

Desain 6 307,61 0,058734

Desain 7 414 0,034522

Desain 8 470,26 0,039084

Desain 9 363,39 0,062924

xxxviii

FIGURE 6. Von Mises Stress distribution under static loading for Ti-6Al-4V material

FATIGUE ANALYSIS Goodman, Soderberg and Gerber theories was used for calculation of safety factor and farigue life of artificial

hip prosthesis. The design should satisfy maximum or an infinite fatigue life. In this research, safety factor and fatigue

life of the prosthesis is evaluated using ANSYS Workbench. Fatigue calculations of the implant are conducted for

CoCrMo and Ti-6Al-4V materials. In this calculation, fatigue material models shown in Figure 7. known as S–N

curves shows fatigue properties of CoCrMo and Ti-6Al-4V alloy in terms alternating stress versus number of cycles.

Stress life (S/N) approach was used for evaluating the fatigue life of the design. In the FEA, the materials are considered

to be elastic and the analysis was performed according to infinite life criteria (109 cycles). Therefore, the stress

amplitude was ensured to be lower than the lowest stress on the S/N curve[6][11][14]. The formulation of goodman,

soderberg and gerber theories can be seen in Table 4.

𝜎𝑚 =(𝜎𝑚𝑎𝑥+𝜎𝑚𝑖𝑛)

2 (1)

𝜎𝑎 =(𝜎𝑚𝑎𝑥− 𝜎𝑚𝑖𝑛)

2 (2)

N = Safety Factor

Se = Endurance Limit (MPa)

Su = Ultimate Tensile Strength (MPa)

𝜎𝑚 = Mean Stress (MPa)

𝜎𝑎 = Alternating Stress (MPa)

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Tabel 4. Fatigue analyses were performed according to Goodman, Soderberg and Gerber methodes.

Figure 7. Fatigue Curve (S-N curve) for CoCrMo and Ti-6Al-4V [11]

Fatigue Theories Formulas

Goodman (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑢

) =1

𝑁

Soderberg (𝜎𝑎

𝑆𝑒

) + (𝜎𝑚

𝑆𝑦

) =1

𝑁

Gerber (𝑁. 𝜎𝑎

𝑆𝑒

) + (𝑁. 𝜎𝑚

𝑆𝑢

)2

= 1

xl

Table 5. Minimum Safety Factor of AHP design under static loading

Material Design Goodman Soderberg Gerber

CoCrMo Design 1 1,689025 1,47715 2,088494

Design 2 1,662822 1,454216 2,056109

Design 3 1,205822 1,054579 1,490994

Design 4 0,964722 0,843714 1,192879

Design 5 0,938201 0,820523 1,160083

Design 6 1,164206 1,018173 1,439544

Design 7 0,782798 0,684618 0,967923

Design 8 0,696983 0,609564 0,861815

Design 9 0,929331 0,812762 1,149119

Ti-6Al-4V Design 1 2,47634 2,36152 3,062017

Design 2 2,438031 2,324973 3,014678

Design 3 2,20897 2,106556 2,731392

Design 4 1,783314 1,700633 2,205071

Design 5 1,65129 1,574727 2,041829

Design 6 1,93721 1,847388 2,395376

Design 7 1,439326 1,372599 1,779717

Design 8 1,267131 1,208386 1,566799

Design 9 1,639839 1,563807 2,027671

From Table 5, we can conclude all new AHP design has different safety factor values according to all fatigue

theories. The AHP design made of Ti-6Al-4V were safe under static loading because it’s material have high yield streng.

In other that the yield strength of CoCrMo is lower than Ti-6Al-4V that make several of AHP design made of CoCrMo

is fail under static loading. Among new AHP design, AHP design 1 with no hole made of Ti-6Al-4V better than the

others in fatigue life. Because this design has higher safety factor value in all fatigue theories. The displacement value

of assembly AHP and femur bone are given in Table 6.

Table 6. Maximum deformation of assembly AHP and Femur Bone under static loading

Material Design Total Deformation (mm)

CoCrMo

Design 1 15,277

Design 2 15,186

Design 3 15,099

Design 4 15,024

Design 5 14,97

Design 6 15,156

Design 7 15,089

Design 8 15,041

Design 9 14,99

Ti-6Al-4V

Design 1 15,468

Design 2 15,381

Design 3 15,298

Design 4 15,227

Design 5 15,177

Design 6 15,354

Design 7 15,291

Design 8 15,249

Design 9 15,198

CONCLUSION

The purpose of this research was to calculated properness of artificial hip prostheses. In this research, nine

different new AHP design for hip prosthesis are created. AHP design have varying geometry and varying number of

holes. The AHP design has hole with varity shape and number on the stem. The number of hole and varying shape are

designed to reduce weight of the implant and to stick the implant to the femur bone securely also increase osseointeration

xli

process. Static FE analyses of AHP have been conducted using ANSYS 19.1. Based on static FE analysis results, safety

factors for fatigue life have been calculated. Fatigue calculations have been carried out for CoCrMo and Ti-6Al-4V

materials based on Goodman, Soderberg, and Gerber fatigue theories. All calculations are performed according to the

infinite fatigue life criteria. Finite element analyses in this study show that several new AHP designs are safe against

fatigue failure. The best AHP design for fatigue under static loading is new AHP design 1 with no hole made of Ti-6Al-

4V material. Several new AHP designs made of CoCrMo is not recommended for Artificial Hip Prosthesis because in

FEA predicted to be unsafe under static loading.

ACKNOWLEDGMENTS

This research was supported by internal funding from the Sepuluh Nopember Institut of Technology

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