Elasto-Plastic Stress Analysis in Laminated Composite Beams

In this study, the elastic-plastic stress analysis is carried out on symmetric laminated composite beam composed of four orthotropic plies. To determine analytically the residual stresses and the expansion of plastic zone for different stacking sequence, a software program is developed and this program makes it possible to establish elastic region, plastic region, the distributions of the elastic, elastic-plastic and residual stress components. The Bernoulli-Euler theory is utilized in the solution for small plastic deformations. For the elastic-plastic solution, the Tsai-Hill Theory is used as a yield criterion. The laminated composite beams are evaluated for linear strain hardening and non-linear strain hardening material properties. Elastic, plastic and residual stress components, equivalent plastic strains and equivalent plastic stress components are given in tables. The distributions of the elastic, plastic and residual stresses throughout the cross-sectional area of the beam are illustrated in figures. Transverse displacement is calculated numerically. Also, finite element analysis is performed, and the finite element results are compared with analytical results.