1. The shaft shown in the figure is machined from AISI 1040 CD steel, with Sut=85 kpsi. The shaft rotates at 1600 rpm, at room temperature, and is supported in rolling bearings at A and B. The applied forces are Fi = 2500 lbf and F2 = 1000 Ibf. Determine the minimum fatigue factor of safety based on achieving infinite life. If infinite life is not predicted, estimate the number of cycles to failure. Also check for yielding. Use reliability of 50%. -8 in -8 in- F1 -8 in F2 17 in ] - in - in 1- in in 1 + -10 in 1 -10 in 1 1 3 in - - in A All fillets ra in R. in B
2. The figure is a drawing of a 4x20 mm latching spring. A preload is obtained during assembly by shimming under the bolts to obtain an estimated initial deflection of 2 mm. The latching operation itself requires an additional deflection of exactly 4 mm. The material is ground high-carbon steel, bent then hardened and tempered. Consider Sut= 1666 MPa, and Modulus of Elasticity E=207 GPa. The inner radius of the bend is 4 mm. Estimate the yield strength to be 90 percent of the ultimate strength. (a) Find the maximum and minimum latching forces. (b) Determine the fatigue factor of safety for infinite life, using the Goodman criterion. F 140 * 20> Section A-A