Fatigue Life of Type 316 Stainless Steel under Wide Ranged Multiaxial Loading

Abstract

Each type of testing machine has its own characteristics, but most of multiaxial fatigue studies have been performed by a push-pull and reversed torsion loading testing machine. This type of testing machine can perform multiaxial fatigue tests under non-proportional loading in which principal directions of stress and strain are changed in a cycle. However, a principal strain ratio range performable in this testing method is −1≤ ϕ ≤−ν, where ϕ and ν are the principal strain ratio and the Poisson's ratio. This study discusses about stress and strain states and multiaxial fatigue testing method. In order to perform fatigue test in −1≤ϕ≤+1 under non-proportional loading, a multiaxial fatigue testing machine of combining the push-pull and reversed torsion loading and cyclic inner and outer pressures is also developed. Then, this paper presents experimental results under several multiaxial loadings carried by the testing machine, too.