Finite element and material models were developed to describe the elastic instability of afiberglass–rubber sandwich composite. The analysis was verified with full-scale testing of twogroups of arched panels with different rubber core materials. The finite element model consistedof solid elements for the rubber core and shell elements to represent the fiberglass skins. Anaccurate description of the nonlinear behavior of the rubber core materials at low strains (<5%)was found to be an important factor in achieving good agreement between analysis andexperiment. This was implemented in Abaqus? software using the hypo-elastic material model.A shell-only representation, which satisfactorily reproduced membrane-dominated behavior,significantly overestimated critical buckling pressures. The buckling pressures predicted by thepresented analyses were 148±7 and 323±24 kPa (21.5±1.0 and 46.8±3.5 psi) for the two groupsof panels. These agreed well with the experimentally measured values of 147±2 and 317±7 kPa(21.3±0.3 and 46.0±1.0 psi), respectively.
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