Associate Professor, Rensselaer Polytechnic Institute, Troy, New York
Pages: 47 Published: Jan 1974
A literature survey was made on the influence of state of stress on the deformation and fracture behavior during low-cycle fatigue. Only the phenomenological aspects of fracture and deformation in the low-cycle range (< 105 cycles) are considered. Most of the materials investigated are shown or are assumed to have isotropic fatigue properties so that anisotropy was generally not considered.
For the isotropic case correlation formulas between uniaxial and multiaxial states of stress (strain) are stated in Appendix 1. Individual papers are reviewed to see which formula can best correlate uniaxial and multiaxial data. No single criterion was found which consistently correlates the data. Of all the correlation formulas the von Mises or distortion energy or octahedral shear stress criterion showed the highest degree of acceptance. However, some papers show no good correlation on the basis of this criterion and serious objections are voiced against this criterion on principal grounds. The von Mises criterion gives the same value for two states of stress which differ only by a hydrostatic pressure, it is pressure insensitive. Fatigue fracture is shown to be affected by the superposition of a hydrostatic pressure and therefore a pressure sensitive criterion should be used for correlation.
In future work a clear distinction of the influence of multiaxial states of stress (strain) on crack initiation and crack growth is necessary. Crack initiation and propagation studies are urgently needed. For isotropic fatigue properties pressure sensitive criteria should be incorporated into the constants of a generalized Coffin-Manson law. In the case of anisotropic fatigue properties, new correlation procedures have to be developed.
Fatigue (materials), fatigue strength, fatigue tests, thermal fatigue, torsional fatigue, triaxial tests, correlation, fractures (materials), life (durability), cyclic loads, stress cycle, plastic deformation, crack propagation, austenitic stainless steels, alloy steels, review, evaluation
Paper ID: STP38944S