Finite element analysis of free edge stresses in non-linear viscoelastic composites under uniaxial extension, bending and twisting loadings

A finite element procedure for the analysis of time-dependent interlaminar stresses in non-linear viscoelastic laminated composites subjected to arbitrary combinations of axial extension, bending and/or twisting loads has been developed based on Schapery's non-linear constitutive relations and Pipes and Pagano's displacement field for laminates under a generalized plane deformation state. Parametric studies are presented to demonstrate the accuracy of the numerical procedures. As illustrative examples, time-dependent non-linear interlaminar stresses for cross-ply and angle-ply laminates subjected to bending and twisting are present. Other layup orientations can be conveniently analysed using the presently developed numerical procedure.