Optimal design of prestressed laminate/ceramic plate assemblies

It is well known that the dynamic compressive strength of ceramics is enhanced by confining compressive stress. The paper shows how a biaxial in-plane compressive stress can be induced in a ceramic layer by encapsulation in a fiber-prestressed composite laminate. Optimal prestress distribution in individual plies of the laminate is found, together with the resulting residual stresses. Large compressive stress, 600-1000 MPa can be supported in an alumina layer by aramid/epoxy of carbon/epoxy laminates of the same total thickness as the ceramic. Stress relaxation due to either temperature changes or matrix creep is found to be of minor significance. Examples present results for specific material systems and laminate layups.