A higher-order theory for plane stress conditions of laminates consisting of isotropic layers

In this paper, a higher-order theory is derived for laminates consisting of isotropic layers, on the basis of three-dimensional elasticity with displa cements as higher-order functions of z in the thickness direction. The theo ry employs three stress potentials, Psi (an Airy function), p (a harmonic f unction), and its conjugate q, to satisfy all conditions of stress equilibr ium and compatibility. Interlaminar shear stresses, ie., antiplane stresses , are shown to be present at the interfaces, especially near material disco ntinuities where gradients of in-plane stresses are usually high. For illus trating its practical application, the problem of a plate containing a hole patched with an intact plate is solved.