Design Criteria for Biaxial/Multiaxial Low Cycle Fatigue

Abstract

This paper discusses a design procedure for structural components subjected to proportional and nonproportional low cycle fatigue damage. Strain multiaxiality and nonproportional factor were introduced for discussing the procedure. The applicability of the multiaxial proportional and nonproportional parameters was examined for the accurate prediction of proportional and nonproportional fatigue lives. A design flow was presented that indicates judging method to use uniaxial, multiaxial proportional or nonproportional damage law. The necessary data for the judgment were the exponent of Coffin-Manson law, a constant that expresses the amount of additional hardening and strain history.

Isothermal and thermo-mechanical fatigue behavior of the nickel base superalloy Waspaloy™ under uniaxial and biaxial-planar loading

“…A modification of this hypothesis was done by Fatemi and Socie [22] and a simplification was suggested by Shamsaei et al [23]. Completely different approaches were used by Sakane et al [24][25][26] and Ogata et al [27,28] which predict the fatigue lives by strain-based hypotheses. Most hypotheses were developed for individual materials as well as the respective stress states and can only rarely be transferred to other stress states and materials.…”

Fast assessment of the critical principal stress direction for multiple separated multiaxial loadings

“…In a less specific way, under non-proportional loading, principal directions change in time; this variation is one of the most tricky problem in the investigation of the multi-axial fatigue damage, since there is not an intrinsic or natural frame of reference where defining the fundamental stress quantities. Several research efforts, in multiaxial fatigue, deal with the definition and computation of critical plane direction or main principal frame of reference; for instance, just few examples can be found in [2][3][4][5]. Specifically, the main principal stress directions can be used to evaluate the consequent shear based critical plane [2].…”