Q1. The tensile load F is to be applied to the tie bar shown in figure below. The diameter of tie bar is 50 mm. The surface of the bar has defects resultant from the manufacturing process; these encompass a maximum depth of 1.5 mm and encompass a shape factor of 1.4. If the fracture toughness of the material employed is 120 MPa m–0.5, find out the maximum load that can be applied if brittle fracture is not to take place. Use a factor of safety of 3.
Q2. Consider that we require predicting the fatigue life of the bracket as shown in figure below. If we are given that the given relationship applies for the bracket:
and that the stress differs cyclically between 30 and 150 MPa, find out the number of cycles for a defect to grow from 1.5 mm to 4 mm.