A Discussion of Negative Poisson's Ratio Design for Composites

It is feasible to design laminated composites with negative Poisson's ratio. Although the minimum value of negative Poisson's ratio design can be done via numerical approach, it is possible to use the analytical method in this paper to perform the following tasks: (a) evaluate the approximated ply orientation angles to obtain maximum transverse strain cy, (b) determine the necessary conditions of design negative Poisson's ratio, and (c) investigate the influence of laminae properties on the Poisson's ratio of a composite laminate. In this study, it is also found that, in general, the ply orientations for obtaining maximum transverse strain, sy, in a composite laminate are close to 70'/20I%.