Prediction of Off-Axis Nonlinear Material Behavior for Unidirectional CFRTP Using Numerical Material Tests

Abstract

This study aimed to examine the nonlinear material behavior of unidirectional carbon fiber reinforced thermoplastics (UD-CFRTP) under off-axis loading using numerical material tests (NMTs). A method to identify the appropriate material properties of an assumed macroscopic anisotropic constitutive law is proposed. To identify the macroscopic material properties using an optimization method, seven macroscopic deformation modes (three vertical directions, three shear directions, and a deformation pattern in the off-axis direction of 45º) were studied for preparing the virtual material responses. Identification accuracy was verified by comparing the predicted macroscopic material responses with those obtained using the actual off-axis tensile test. The extensive use of the NMTs with seven macroscopic deformation modes enabled the successful confirmation of the material properties of the assumed macroscopic constitutive law for UD-CFRTP. This was identified by comparing the NMT results obtained using the off-axis macroscopic deformation and standard six modes with those obtained using only six modes.