Inverse procedure for mechanical characterization of multi-layered non-rigid composite parts with applications to the assembly process

In assembly process, non-rigid parts in free-state may have different forms compared to the designed model caused by gravity load and residual stresses. For non-rigid parts made by multi-layered fiber-reinforced thermoplastic composites, this process becomes much more complex due to the nonlinear behavior of the material. This paper presented an inverse procedure for characterizing large anisotropic deformation behavior of four-layered, carbon fiber-reinforced polyphenylene sulphide, non-rigid composite parts. Mechanical responses were measured from the standard three points bending test and the surface displacements of composite plates under flexural loading test. An orthotropic hyperelastic material model was implemented as a UMAT user routine in the Abaqus/Standard to analyze the behavior of flexible fiber-reinforced thermoplastic composites. Error functions were defined by subtracting the experimental data from the numerical mechanical responses. Minimizing the error functions helps to identify the material parameters. These optimal parameters were validated for the case of an eight-layered composite material.