Bridging machining simulation and fatigue analysis

Machining processes subject materials to extreme plastic deformation and significant temperature increases within milliseconds, profoundly altering surface integrity. These effects - including residual stresses, microstructural changes, and strain hardening - can significantly influence fatigue life. While well understood in principle, such machining-induced effects have historically been difficult to integrate into fatigue life calculations, limiting manufacturers' ability to optimise machining parameters without increasing the risk of premature component failure.

To overcome these difficulties, MISUTECH and HBK developed an interface between MISUTECH's MISULAB machining simulation software and HBK's nCode DesignLife fatigue analysis solution. MISULAB predicts the effects of machining on surface integrity, including three-dimensional residual stress fields generated during machining. These residual stress fields are seamlessly transferred into nCode DesignLife alongside mechanical loading conditions, enabling fatigue analysis that accounts for both manufacturing and in-service stresses.

This combined solution allows engineers to rapidly evaluate multiple machining strategies, assess the fatigue impact of new cutting tools or process changes, and optimise machining parameters - all without the need for extensive physical machining trials or long-duration fatigue testing.

By incorporating machining-induced material states directly into fatigue assessments, manufacturers can simultaneously optimise machining costs and component strength. In one demonstrated application involving an aerospace power transmission shaft, optimised machining conditions that avoided harmful residual stresses resulted in dramatically improved fatigue performance compared to conventional turning conditions.