Model Updating of Constitutive Relation of Ti64 Alloy Based on Gleeble Testing

Abstract This study investigates the mechanical behavior of Ti64 alloy at high temperature (750°C) using digital twinning technology based on finite element analysis in combination with Gleeble testing. In the realm of high-temperature alloy materials, empirical constitutive models, such as the Johnson-Cook constitutive relation, have conventionally been utilized to delineate the mechanical behavior of metallic substances under conditions of elevated temperatures and strain rates. This research applies a modified Johnson-Cook model tailored specifically for characterizing the unique strength hardening mechanisms inherent to Ti64 alloy. Subsequently, computational simulation is conducted to implement the modified Johnson-Cook model within finite element analyses. Furthermore, to address the computational challenge inherent in finite element simulation based inverse analysis through optimization, a multi-response Gaussian process model is constructed as a surrogate model to replicate thermomechanical analyses, thereby facilitating efficient simulation. Finally, the parametric identification is cast into an optimization problem, that minimizes the difference between Gleeble testing results and the model prediction in the parametric space, to determine the model parameters of the modified Johnson-Cook model. This framework is successfully applied to the model updating of Ti64 alloy. The algorithms, including the custom user subroutines and the parameter identification process, provide valuable tools for exploring the constitutive relations of various alloys.