Mechanical properties of composite laminates patches with an aluminum substrate

A stress distribution of composite patch with an aluminum substrate was obtained by using stress functions and Kantorovich method when the substrate was under uniaxial extension and pure bending moment. The principle of complementary virtual work was applied to obtain the governing equations. The obtained three-dimensional stresses satisfied the traction free conditions at the free edges and the top surface of the patch. The stress of the bottom surfaces of the patch was obtained from the equilibrium state of patch and substrate. The interlaminar stresses reached maximum at the free edge and decreased quickly at the inner part of the patch. To demonstrate the validity and efficiency of the proposed method, cross-ply, angle-ply, and quasi-isotropic laminates patches were studied. Since the proposed analysis accurately predicts three-dimensional stresses in a composite patch not only uniaxial extension case, but also pure bending case, it is promising to use as an efficient tool for analyzing and designing such aerospace structural component.