Investigation on bending behavior of shape memory polymeric composite beam with a corrugated skin

In this paper, a sandwich beam of a SMP material which have a corrugated core is studied. The corrugated core is from a polymeric material. Structures with corrugated profiles show higher stiffness-to-mass ratio in the transverse to corrugation direction compared to flat structures. As a result, the beam with corrugation along the transverse direction is stiffer than the one with corrugation along the beam length. The flexural behavior of the composite corrugated beam is studied employing a developed constitutive model for SMP and the Euler-Bernoulli beam theory. The constitutive model utilized is in integral form and is discretized employing finite difference scheme. To verify the results of the Euler-Bernoulli beam theory and finite difference method, finite element models of different corrugated sections have been simulated in a 3D finite element program. The results demonstrate that the developed model for the composite beam presented in this study predicts the behavior of the beam successfully. The sandwich beam with different corrugated cores (triangular, sinusoidal and trapezoidal shapes) are compared with each other. Also, results show that the shape fixity is decreased a little, like any other reinforcing method. This decrease in shape fixity results in increase of load capacity in composite beams. The stress-free strain recovery and constrained stress-recovery cycles are both studied.