Calculation of the Fatigue Life of a Surface-Hardened Shaft by the Finite-ElementMethod

摘要

The problems encountered in machine component design are discussed. Theseproblems arise when the material properties vary in the load carrying cross section and when purely elastic design is unsuitable, that is, when fatigue may be an imminent failure mechanism. Solution procedures are carried out by an elastoplastic finite element calculation for the surface hardened cylindrical shaft in bending, torsion and combined bending torsion. The effective plastic strains in the cross section of the shaft are calculated and the fatigue life of the shaft is predicted according to the local strain approach. The analyzed shaft is surface hardened by induction heating, the hardness and other material properties thus varying between the core and the surface. The loading is bending or torsion. Only the monotonic first quarter cycle of the loading is calculated. The fatigue life is evaluated using the calculated effective plastic strain amplitude.