Microscale modeling of rate-dependent failure in thermoplastic composites under off-axis loading

In this paper we develop a finite deformation micromechanical framework for modeling rate-dependent failure in unidirectional composites under off-axis loading. The model performance is compared with original experiments on thermoplastic carbon/PEEK tested at different strain-rates and angles. To achieve quantitative agreement the experiments, microcrack initiation criterion based local stress rate of state polymer matrix proposed. Microcracking represented by cohesive zone model, special attention to inclusion geometric nonlinearity formulation. regard, extension an existing formulation three-dimensional space. Beside microcracking, Representative Volume Element (RVE) also accounts viscoplasticity matrix. A recently introduced dedicated arclength control method utilized impose strain-rate micromodel. Accordingly, kinematic relations governing RVE allow change orientation micromodel loading process. This microstructure has important implication apparent material strength.