State space approach for stress decay in laminates

Stress decay in laminates due to edge boundary e€ects are studied through a state space formulation. A self- equilibrium eigenstress ®eld accounting for the multilayer construction of the laminate is derived using the state variables and the transfer matrix method. The eigenvalue determination requires only the solution of 6 6 determinants irrespective of the number of laminae. Through combinations of the eigenstress ®eld and the interior stress ®eld a complete solution valid in the boundary layer as well as in the interior region of the laminate can be obtained. For veri®cation, the formulation is ®rst applied to determining the eigenstress in a homogeneous anisotropic layer, and then the free edge stress decay in laminates under uniform extension is examined