Active control of interlaminar stresses in laminated composites by through-thickness thermal gradients

In this paper, we propose a method to actively control interlaminar stresses near the free edges of laminated composites by through-thickness thermal gradients. Theoretical solutions are given for optimal steady-state through-thickness temperature distributions under uniaxial loading that are required to eliminate or reduce the interlaminar stresses below a prescribed level. The optimal solutions are obtained by minimizing appropriate performance indices that are functions of the far- field properties, with respect to the through-thickness temperature differences. In the second part, an experimental investigation is conducted on a glass/epoxy cross-ply laminate with embedded piezoelectric sensors and a thermal heater. Through the experiment, a feasibility of the thermal control of interlaminar stresses is demonstrated.