Question 1: (6 marks) A stepped shaft ground from AISI 1040 annealed steel is subjected to torsion, as shown in Figure 1. Determine the value of a. The torque T to produce static yielding b. The maximum fully reversed torque 7 that can be applied while having infinite fatigue life (Assume non- rotating shaft) Given: D= 50 mm, d = 25 mm, r = 1.25 mm. 98 Assumption: Reliability is 99%. AISI No. Treatment Q&T* Q&T* 1030 1040 Q&T* Q&T* Q&T* Normalized Annealed Q&T Q&T Q&T Normalized Annealed 3 Temperature C (F) 205 (400) 315 (600) 425 (800) 540 (1000) 650 (1200) 925 (1700) 870 (1600) 205 (400) 425 (800) 650 (1200) 900 (1650) 790 (1450) 4 Tensile Strength MPa (kpsi) 848 (123) 800 (116) D 731 (106) 669 (97) 586 (85) 521 (75) 430 (62) 779 (113) 758 (110) 634 (92) 590 (86) 519 (75) EFT 5 Yield Strength, MPa (kpsi) 648 (94) 621 (90) 579 (84) 517 (75) 441 (64) 345 (50) 317 (46) 593 (86) 552 (80) 434 (63) 374 (54) 353 (51)