Compressive buckling analysis of sandwich panel to composite plate with adhesive bonding using GDQM

This study investigates the compressive buckling behavior of composite plates adhesively bonded to rectangular sandwich panels. The critical buckling loads are determined using the Generalized Differential Quadrature Method (GDQM) based on the First-Order Shear Deformation Theory (FSDT), which incorporates compatibility conditions at the adhesive interface. The governing relations of the lap-joint setup are formulated based on the principle of minimum potential energy (MPEP). The effects of several parameters, including sandwich core thickness, boundary conditions, and face sheet and plate materials are evaluated. The adhesive layer response under buckling conditions is also examined. Parametric studies are conducted on multilayer composites made of glass/epoxy, carbon/epoxy, and aramid/epoxy, bonded with epoxy, AV-138, and IPCO-9923 adhesives. The influence of material properties, joint overlap, geometric aspect ratio, adhesive-to-plate thickness ratio, and boundary constraints on the critical buckling capacity is comprehensively assessed. Additionally, adhesive failure is evaluated to ensure it does not precede structural buckling. The findings show that a thicker core leads to higher critical buckling loads and shifts the buckling zone from the sandwich panel to the composite plate. Higher overlap ratios and stiffer upper and lower face sheet materials significantly enhance the buckling capacity. Among the tested configurations, unidirectional carbon/epoxy laminates bonded with AV-138 adhesive exhibit the highest critical buckling loads. The analytical findings are validated through finite element simulations using ABAQUS, showing excellent agreement with the proposed model.