Question

augue application? 6-10 A rotating shaft of 25-mm diameter is simply supported by bearing reaction forces R and R2. The shaft is loaded with a transverse load of 13 kN as shown in the figure. The shaft is made from AISI 1045 hot-rolled steel. The surface has been machined. Determine (a) the minimum static factor of safety based on yielding. (b) the endurance limit, adjusted as necessary with Marin factors. (c) the minimum fatigue factor of safety based on achieving infinite life. (d) If the fatigue factor of safety is less than 1 (hint: it should be for this problem), then estimate the life of the part in number of rotations. Mechanical Engineering Design 364 200 mm 50 mm- 25 mm- 13 kN Problem 6-1O R Not to seale.

Answer 1

For AISI I045 HR Sut 510 MPa Syt Consider shaft FBD MRI 0 R2 (200)-13(150) = 0 R29.75 KN EFyo RitR2=ろ R1=3.25 KN Mmax .75(50) 487-5 KN-mm Te MmaxC Tid3 ニ 32 (A87.5 x103) T7 (25)3 『ev=ろI7:8 MPa ofoafety a) The inimim otatic jactor based yicldeng ろ10 Sy 311-8 y-0.97

Se-0.50ut = 0 5 (510) = 285 MPa Ra zasu 451 (510)060 839 Kb=4d107124 (25 - 0.818 kc = -O.I07 Se kakbkesk (0-839)10.87s)) (285) Se R09.9 MPa fatique factor of safety Minimem 209.9 3I7.8 Se Trev inferite life is not d) Sut redicted 570 ksi= 82:1 ks i E.89 6-18 with St 827 ksi, f-0.97 aSut 014x510) 1468.4 209.q Se 우)0이두 -()60이우 그억 = 52 x104 cyoles O.914 x670 209.9 -0.14 Se N( b / 317.8 (468 4