Abstract:

ESDU 84018 introduces a Fortran program (ESDUpac A1043) for failure analysis of the laminate subjected to consecutive systems of combined in-plane, moment and thermal loading. Initially unrestrained balanced or unbalanced laminates can be treated, as can the effect of holding the unloaded laminate flat. The failure assessment is based on a linear elastic layer-by-layer analysis in which the stresses in each layer in turn are compared to the Puck Modified Criterion (see also ESDU 83014) which differentiates between fibre and matrix failures. If matrix failure occurs, the transverse direct and shear stiffnesses of that layer are put to zero but the fibre stiffness properties are retained. The development of such layer failures is traced under the gradual application of the loading system to provide a damage history. Laminate failure is assumed either when total matrix failure occurs or when fibre failure in one layer occurs. If failure does not occur, the program provides an assessment of the load level that would cause failure.