Residual stress analysis in symmetric thermoplastic laminated plates under thermal loads: Analytic solution

In this paper, thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply [0 degrees/90 degrees](2) and angle-ply [15 degrees/-15 degrees](2), [30 degrees/ -30 degrees](2), [45 degrees/-45 degrees](2), [60 degrees/-60 degrees](2) thermoplastic laminated plates under various temperature change through the thickness of plates. The plates are composed of four orthotropic layers bonded symmetrically. In the solution, a special computer program has been employed. The composite materials are assumed to be strain hardening. The Tsai-Hill Theory is used as a yield criterion. Residual stresses are determined in the symmetric cross-ply and angle-ply laminated plates for small deformations. The intensity of stress components in the symmetric cross-ply laminated plate is higher than in angle-ply laminated plate due to the differences among the stiffnesses of layers. Plastic yielding occurs in all the laminated plate at the same temperature.