A Theory for Fatigue Failure under Multiaxial Stress-Strain Conditions

TLDR

The theory is compared with several classical and recent theories, which are briefly reviewed. The authors propose a new multiaxial fatigue theory based on a physical interpretation of fatigue crack growth mechanisms. The theory is expressed by contours of constant life defined by principal strains ε1, ε2, ε3 (ε1 ≥ ε2 ≥ ε3) and captures the influence of both shear strain and tensile strain normal to the maximum shear plane. The resulting equation emphasizes the role of strain parameters in correlating fatigue data, and demonstrates that classical fatigue theories fail to predict experimental results and could be hazardous for design.

Abstract

A new theory for multiaxial fatigue is presented that is based on a physical interpretation of the mechanisms of fatigue crack growth. It may be represented graphically by contours of constant life, which are expressed mathematically by where ε 1 , ε 2 and ε 3 are the principal strains, •ε 1 ≥ ε 2 ≥ ε 3 . This equation underlines the importance of strain parameters in correlating fatigue data. It illustrates the effect of both the shear strain and the tensile strain normal to the plane of maximum shear. The theory is compared with several classical and recent theories, which are briefly reviewed. It is shown that classical theories of fatigue failure cannot correlate experimental data, and may be dangerous if used for design purposes.