1. A 1.5-inch round bar has been machined from AISI 1050 colddrawn round bar. This part

is to withstand a fluctuating tensile load varying from 0 to 16 kip. Because of the design

of the ends and the fillet radius, a fatigue stress-concentration factor of 1.85 exists. The

remaining modification factors have been worked out, and are ka = 0.797, kb = kd = 1, and

kc = 0.923. Find the factor of safety using the Goodman interaction line.

2. For the state of plane stress shown, (a) construct Mohrs circle, determine (b) the

principal planes, (c) the principal stresses, (d) the maximum shearing stress and the

corresponding normal stress.

3. A spherical shell of 800 mm diameter is subjected to an internal pressure of 2 N/mm2.

Find the thickness required for the shell if the safe stress is not to exceed 100 MPa.

4. A leaf spring in an automobile is subjected to cyclic stresses. The average stress = 150

MPa; variable stress = 500 MPa; ultimate stress = 630 MPa; yield point stress = 350 MPa

and endurance limit = 150 MPa. Estimate, under what factor of safety the spring is

working, by Goodman and Soderberg formulae.

5. A water tank, 22 ft in diameter, is made from steel plates that are 1/2 in. thick. Find the

maximum height to which the tank may be filled if the circumferential stress is limited to

6000 psi. The specific weight of water is 62.4 lb/ft3.