A novel approach for the strain rate dependent modelling of woven composites

摘要

This study proposes a new computational model for polyamid-matrix woven composites that takes into account rate effects for high speed impact applications. The rate effects are captured solely through the use of a spectral viscoelastic model, used in parallel with a conventional damage elastic-plastic model. It appears that, for very different load rates, neither plasticity nor damage kinetics need any first order rate dependency to capture the nonlinear envelope response until failure. To verify this hypothesis, a dedicated experimental setup is proposed that allows strain-controlled interruption of high speed tension loadings. Cycled loading sequences may therefore be applied to a sample even in the dynamic regime, and loss of stiffness and irreversible strains may be measured until total failure. A specific and rigorous identification procedure is proposed to that effect. Our experimental findings confirm the ability of the model to predict both the envelope response curve and the evolution of the internal mechanisms at very different strain rates.