Question

S = 200 kpsi A steel shaft in bending has an ultimate strength of 690 MPa and a shoulder with a filler radius of 3 mm connecting a 32 mm diameter with a 38 mm diameter. Estimate the fatigue stress concentration factor, Kf, using Figure 6-20. 0 0.5 1.0 3.0 3.5 4.0 1.0 Notch radius r, mm 1.5 2.0 2.5 (1.4 GPa) (1.0) (0.7) 0.8 150 (0.4) 100 0.6 60 Notch sensitivity a 0.4 Steels Alum, alloy 0.2 0 0 0.02 0.04 0.12 0.14 0.16 0.06 0.08 0.10 Notch radius r, in 3.0 Figure A-15-9 Round shaft with shoulder fillet in bending. , = Mc/1, where c -d/2 and / -7d/64. 2.6 M 1231 Id M 2.2 K 1.8 Did 3 1.5 1.10 1.02 1.05 1.0 0.05 0.10 0.20 0.25 0.30 0.15 old Hint: Follow Example 6-6. Use Figure A-15-9 (Appendix) to estimate Kt and Figure 6-20 to estimate q. Use the following formula to calculate KF. Kf = 1 + (kt - 1) a. 0.53 b. 1.11 C. 0.75 d. 1.55 e. 3.29

Answer 1

Ultimate Edsength diven, - Goo MPa = 100ksi Sue d=32mm notch sadiro de 3 mm. D=38 mm Using graph of 9 vs e At Sut = looks & r=3 mm. for sted stoft, t 19 0.85 Capprox2 Using graph of Kg vs z d ir d 3 - 0.09375 h 0.10 32 = 1.1875 D. 1.19 At r d 0,10 & D a of 35 1.19 → [ky = 1.65 Now, fatigue stress concentsation sisese concentration factor CKD Kf = 1 + 9 CK - 1) KA = 1 + (0,85) (1.65 - 1) Kp = 1,55 Comed Answer Option @ 1.55