Nonlinear Rate-Controlled Deformation of Unidirectional CFRP under In-Plane Shear Conditions

When designing thin-walled structures made of composite materials, the fundamental initial data are the unidirectional layer characteristics which depend to a large extent on the properties of the matrix and its adhesion to the fiber. In this paper, using the Rabotnov nonlinear constitutive relation, the regularities of deformation of a unidirectional carbon fiber-reinforced thermoplastic at high temperature under in-plane shear conditions are described. The application of the properties of resolvent operators used in hereditary mechanics of solids and the choice of approximation of the instantaneous stress–strain curve made it possible to invert the Rabotnov constitutive relation. Comparison with the experimental results showed the correctness of the proposed approach.