Simultaneous determination of virtual fields and material parameters for thermo-mechanical coupling deformation in orthotropic materials

In this paper, an effective general method is proposed to determine the optimal virtual fields and extract the elastic constants and the thermal expansion coefficients of orthotropic composite materials from the coupled thermo-mechanical deformation fields simultaneously. First, a practical analysis procedure is implemented based on the assumed material parameters with orthotropic in-plane properties to determine the effective virtual fields for three-point bending test configuration. Six thermo-mechanical parameters of three kinds of orthotropic composite materials are decoupled and identified by the determined effective virtual fields to verify its independence on material parameters. Second, the influences of specimen dimensions and external loadings on identified material parameters are investigated to validate the applicability of effective virtual fields under different test configurations. Finally, the optimal virtual fields are determined by means of a numerical method and its capacity for decreasing the noise influence is investigated quantitatively. The research work will provide an effective method to determine the optimal virtual fields for decoupling the thermo-mechanical coupled deformation of orthotropic composite materials.