A cubic spline layerwise spectral finite element for robust stress predictions in laminated composite and sandwich strips

A new theoretical and numerical tool, comprising of a novel cubic Hermite spline layerwise theory and a spectral strip finite element with integration points collocated to its nodes and high-order polynomial shape functions, is evaluated regarding its capability to predict intralaminar and interlaminar stresses in laminated and sandwich composite strips. Stress predictions in various laminated and thick sandwich beams are presented and compared with exact solutions, high-fidelity plane-strain FE models and reported zig-zag layerwise models. Emphasis is placed on the capability of the present model to predict interlaminar stresses on the free-edges, at ply interfaces, in resin-rich layers and in laminates with artificial delaminations. All numerical results illustrate the capabilities of the present computational tool to provide accurate and robust interlaminar stress predictions implementing coarse discretization, thus ensuring the validity and rapid convergence of the combined higher-order layerwise laminate theory and spectral finite element model. •Combination of a cubic spline layerwise theory and a spectral finite element model.•Interlaminar shear stress compatibility conditions for stress continuity at ply interfaces.•Stress predictions at free-edges, ply interfaces, resin-rich layers and artificial delaminations.•Excellent correlation with reference benchmark solutions in terms of accuracy and computational speed.•Attractive candidate for the analysis of delamination propagation problems.