Residual Stress Analysis in Symmetric Thermoplastic Laminated Plates Under Thermal Loads: Analytic Solution

Abstract

In this paper, thermal elastic-plastic stress analysis is carried out on simply supported symmetric cross-ply [0°/90°]2 and angle-ply [15°/-15°]2, [30°/-30°]2,[45°/-45°]2,[60°/-60°]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.