Development of a Fatigue Model for Low Alloy Steels Using a Cycle-Dependent Cohesive Zone Law

Abstract

A fatigue model for SAE 4130 steels is developed using a cycle-dependent cohesive zone law. Reduction of fracture energy and degradation of stiffness are considered to describe failure resistance after certain number of cycles. The reduction rate of fracture energy is determined with experimental stress ( S )- number of cycles to failure ( N ) scatter found in the literature. Three-dimensional finite element models containing a cohesive zone are generated with commercial software (ABAQUS). Calculated fatigue lives at different stress ratios are in good agreement with experimental ones. In addition, fatigue behavior of hardened SAE 4130 steels is predicted with that of normalized material.