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A 3D orthogonal woven S2-glass composite is investigated using finite element micromechanics to characterize the stiffness and the strength. The methods are applied to a targeted parametric investigation of the effects of stitch density on strength properties and potential benefits of through-thickness reinforcement, such as resistance to transverse shear and delamination, with some consequent loss of in-plane properties. Direct modeling of the exact microstructure from scanning electron microscope visualization provides a precise knowledge of the mechanics and the failure modes of the microstructure under various loading conditions. Modeling results are verified by comparison to experimental data. In-plane stiffness and strength are predicted with 90% or better accuracy. Transverse shear stiffness was less well predicted, but strength was still predicted within 86% accuracy.

An analytical model and numerical approach to predict the effective mechanical properties of a composite conductor consisting of metallic core and insulation layers are presented in this paper. The analytical model was developed based on a two-step homogenizations and mechanics analysis for composite unit cell. The Step 1 homogenization derives the effective properties of the out-wrapped composite insulation layers. The Step 2 homogenization further smears the metallic core and the effective composite insulation layers to develop homogenized mechanical properties for composite conductor according to appropriate homogenization sequences. The procedure of using numerical approach and finite element method to determine the unit cell effective constants were also described and the results of the FEA prediction were presented. The analytical predictions were compared well to the numerical results for the nine material constants that characterize the effective mechanical properties of the composite conductor.