OS0520 Negative Poisson's Ratio in Elastic-Viscoplastic Behavior of Angle-Ply CFRP Laminates : Analysis Based on a Homogenization Theory
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In this study, negative through-the-thickness Poisson's ratios of angle-ply CFRP laminates are investigated macroscopically and microscopically using a homogenization theory for time-dependent composites. For this, first, an angle-ply CFRP laminates are modeled as heterogeneous materials composed of fibers and a matrix. Then, a multiscale elastic-viscoplastic analysis method for the laminates based on a homogenization theory for time-dependent composites with point-symmetric internal structures is proposed. Moreover, the substructure method is introduced into the method to enhance computational efficiency. Using this method, elastic-viscoplastic Poisson's ratios of angle-ply carbon fiber/epoxy laminates subjected to macroscopic uniaxial tension are analyzed. The analysis results obtained are used to demonstrate the negativity of through-the-thickness Poisson's ratios in the viscoplastic region and their variation with the degree of viscoplastic deformation.
