Powerful calibration strategy for the two-layer viscoplastic model

An efficient numerical integration scheme is proposed for the uniaxial loading of the two-layer viscoplastic (TLVP) model, which is a built-in material model in the commercial finite element software Abaqus. The particular version of the TLVP model under investigation is governed by linear isotropic plastic hardening rule with time-hardening nonlinear creep law. The new integration scheme can be easily implemented in any programming environment leading to a fast and robust tool to obtain the stress response in uniaxial loading for a given input strain history. The accuracy of the proposed algorithm is demonstrated and validated by comparing the results obtained with it to those calculated by Abaqus. A new calibration software with a graphical user interface is developed, which can fit the material parameters to the experimental data with arbitrary strain history in a uniaxial loading case. The new software is freely available to download from the webpage of the authors, and it is free to use for research purposes. The excellent performance of the new program is demonstrated by fitting the material parameters to three distinct experimental data sets.