Experimental and theoretical research on the dynamic properties of 3D orthogonal woven E-glass fiber/epoxy composites

The dynamic properties of 3D orthogonal woven E-glass fiber/epoxy composites were studied experimentally under both the dynamic and static loading conditions, and the stress-strain curves were obtained. The results show that the responses of the composites are of obviously nonlinear and anisotropic characteristics, and of the strain rate sensitivity as well. In theory, a macroscopic damage variable dependent of strain and strain rate is put forward to describe these characteristics, and a nonlinear viscoelastic model is presented for the composites with damage. The stress-strain curves fitted by the modified constitutive equation are in good agreement with the experimental ones.