Multi-scale modeling of the viscoelastic behavior of 3D woven composites

A method is presented to predict numerically the homogenized viscoelastic behavior of 3D woven composites using only its constituents' behavior. It is based on elastic homogenizations applied to the Laplace-Carson transform of the time-dependent viscoelastic behavior of the constituents. Two scale changes are necessary: from micro- to meso-scale to obtain the homogenized behavior of the consolidated yarns, and from meso- to macro-scale. The temperature and cure dependent viscoelastic behavior of the matrix is identified from experimental data, using the time-temperature superposition principle with the cure dependent glass transition temperature as reference temperature. The meso-scale representative unit cell of the composite is extracted from X-ray microtomography images. The homogenized viscoelastic behavior is used to calculate the evolution of the apparent moduli of the composite with temperature between -50°C and 200°C. The results are in good agreement with experimental data over the temperature range where the matrix behavior was properly identified.