ELASTIC–PLASTIC STRESS ANALYSIS OF LAMINATED COMPOSITE BEAMS UNDER LINEAR TEMPERATURE DISTRIBUTION

Abstract

This study deals with elastic–plastic stress analysis of symmetric laminated composite beams with perfectly clamped ends under linear temperature distribution. The Bernoulli–Euler theory is used during the solution considering infinitesimal small deformations. The composite beam is assumed to be linear strain hardening. The Tsai–Hill theory is used as a yield criterion in the solution. The stacking sequences of the composite beam are chosen as (90°/0°)s, (30°/−30°)s, (45°/−45°)s, (60°/−60°)s and also (0°)4 and (90°)4 in comparison with the composite beam of a single layer in the literature. The results obtained are in good agreement with the literature. The temperature that causes plastic yielding is found to be highest for the (30°/−30°)s stacking sequence, in order to compare with the others, except for the (0°)4 orientation. Residual thermal stresses are particularly important because they can increase the strength of the composite or may lead to premature failure. The residual stress components (σ x ) r are found to be highest at the upper and lower surfaces. When the plastic region expands further with increased temperature, the residual stress components become highest at the elastic–plastic interface.