An Integrated Approach to Constitutive Modeling and Life Prediction for Automotive Materials

An integrated approach of constitutive modeling and life prediction is presented through introduction of the integrated creep-fatigue theory (ICFT). The ICFT is formulated based on participating deformation and damage mechanisms, which not only describes the cyclic deformation behavior but also the life and fracture mode. Automotive exhaust system materials such as ductile cast iron and austenitic cast steel are used as example materials for demonstration in good agreement with experimental results and metallurgical examinations. This enlightens the understanding of the roles each mechanism plays in low-cycle fatigue (LCF) and thermomechanical (TMF) processes, thus helping material and component design specifically targeting the most damaging mechanism(s) encountered in service.