The influence of the apparent shear modulus on the response of transversely isotropic soft materials under simple shear

摘要

The main purpose of this work is to investigate the mechanical behavior of transversely isotropic soft materials subjected to simple shear when the shear loading is applied perpendicular to the orientation of the fibers. The effect of the continuous fibers with fixed ends on the apparent shear modulus of composites was considered. In the experimental test, unidirectional composite specimens with distinct volume fractions of fibers were fabricated and subjected to simple shear deformations. A mathematical model based on a strain-energy function of two invariants was introduced to predict the shear response of composites at small and large deformations. In this model, a closed-form expression of the apparent shear modulus was proposed considering shear and bending contributions. The neat matrices and the fibers were characterized and all estimated properties were used as input data in order to predict the behavior of the soft composites. Supplementary experimental tests and numerical simulations were performed to verify the predictive model for the apparent shear modulus. A good agreement between the experimental/numerical data and the theoretical model was obtained for small and large deformations. Results showed that the proposed model is capable of predicting the influence of the height and the radius of gyration of the fibers on the apparent shear modulus, and consequently the shear response of the soft composites can be obtained.