Ultimate strength assessment of laser-welded web-core sandwich panels under combined loading conditions

Metallic sandwich panels may be subjected to combined loads, which can substantially reduce their load-carrying capacity. This study investigates the ultimate strength of laser-welded web-core sandwich panels under combined loading using nonlinear finite-element analysis, with geometric imperfections and weld rotational stiffness explicitly considered. Four representative geometries are examined to characterize the shear response, assess its consistency with an analytical estimate, and identify a representative configuration for detailed combined-load analysis. The results show that in-plane shear is the dominant factor governing strength degradation, while lateral pressure provides an additional weakening effect that becomes more pronounced at high shear levels. Increasing weld rotational stiffness improves ultimate strength, although the benefit diminishes beyond a sufficiently high stiffness. A separate 135-case study under pure longitudinal compression identifies core spacing as the primary geometric parameter controlling compression-induced local stability; the resulting reference dimensions are intended as baseline screening indices rather than universal combined-load design rules.