Effect of microstructural features on the fatigue behavior of the valve mechanism cam rolling contact

Abstract

This study introduces a methodology that incorporates gradient structural features and crystal plasticity for assessing contact fatigue in engine valve cams. It explored the influence of grain characteristics and structural gradients on fatigue failure through the lens of Plastic Strain Energy Density (PSED). Findings indicate that variability in crystal orientation significantly impacts PSED and subsequent crack initiation. Additionally, shot peening induces a gradient in grain size, promoting orderly deformation, stress alleviation, and improved fatigue resistance. The study suggests that an optimal fatigue resistance in cam contacts is achievable with a gradient layer comprising 75% volume fraction, which strikes a balance between cost and technical feasibility.

Keywords

• valve mechanism cam
• gradient structural features
• rolling contact fatigue
• crystal plasticity