An elastic¯plastic stress analysis of thermoplastic composite beams loaded by bending moments

In this study, an elastic¯plastic stress analysis is carried out on a high-density thermoplastic-based composite cantilever beam loaded by a bending moment at the free end. The composite beam is reinforced unidirectionally by steel fibers, at 0°, 30°, 45°, 60° and 90° orientation angles. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli¯Navier hypotheses. It is found that the intensity of the residual stress component of sigmax is maximum at the upper and lower surfaces or at the boundary of the elastic and plastic regions. The composite material is assumed to be strainhardening. The Tsai¯Hill theory is used as a yield criterion. The displacement components are found in the elastic region