ONE-DIMENSIONAL ELASTO-PLASTIC MATERIAL MODEL WITH DAMAGE FOR A QUICK IDENTIFICATION OF THE MATERIAL PROPERTIES

Material parameters for elastic, plastic and damage behavior of low-molecular-weight epoxy resin CHS-EPDXY 520 hardened with CHS-P 11 are identified in the paper. Uniaxial cyclic static tests were performed on specimens in line with the ASTM standard D638 - 10 using a Zwick Roell/Z050 test machine with a BTC-Exaclbi.001 clip-on biaxial extensometer. Poisson's ratio and tensile strength were calculated directly from the test results. Other parameters were identified using a combination of a one-dimensional material model, which assumes the infinitesimal strain theory and takes into account elastic, plastic and damage behavior and the optimization method. The model is coded in Python and the values of the material parameters are identified using the optiSLang optimization software. The optimization process uses simple design improvement and gradient-based algorithms with the goal to minimize the difference between the force-elongation curves recorded during the tests and those calculated with the proposed model.