Multi-scale modeling of the thermo-viscoelastic behavior of 3D woven composites
Résumé
A multi-scale modeling strategy is proposed that takes into account the temperature and cure dependence of the viscoelastic behavior of the constituent materials of a composite material and the effects of stress relaxation on thermal expansion and chemical shrinkage. A homogenization strategy is presented, which, starting from the constituent behaviors, yields the homogenized viscoelastic behavior of the composite with time-dependent expansion coefficients. This time-dependence is a direct consequence of the viscoelastic behavior of the constituents, as their expansion coefficients are supposed to be time-independent. In the simulation of a heating process, the model predicts sign changes in the thermal strain rate due to residual stress relaxation close to the glass transition temperature, which cannot be obtained with classical thermo-elastic homogenization methods.
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