Interactive software for material parameter characterization of advanced engineering constitutive models

Abstract

The development of an overall strategy to estimate the material parameters for a class of viscoplastic material models is presented. The procedure is automated through the integrated software COMPARE (COnstitutive Material PARameter Estimator) that enables the determination of an ‘optimum’ set of material parameters by minimizing the errors between the experimental test data and the model's predicted response. The core ingredients of COMPARE are (i) primal analysis, which utilizes a finite element-based solution scheme, (ii) sensitivity analysis utilizing a direct-differentiation approach for the material response sensitivities, and (iii) a gradient-based optimization technique of an error/cost function. Now that the COMPARE core code has reached a level of maturity, a graphical user interface (GUI) was deemed necessary. Without such an interface, use of COMPARE was previously restricted to very experienced users with the additional cumbersome, and sometimes tedious, task of preparing the required input files manually. The complexity of the input containing massive amounts of data has previously placed severe limitations on the use of such optimization procedures by the general engineering community. By using C++ and the Microsoft Foundation Classes to develop a GUI, it is believed that an advanced code such as COMPARE can now make the transition to general usability in an engineering environment.