Sensitivity of structurally loaded sandwich panels to localized ballistic penetration

Abstract: This paper describes a series of tests focused on the combination of structural loading (bending, shear) and simultaneous penetrating impact on sandwich panels with thin GFRP face-sheets, with emphasis on the specific damage morphologies and developments depending on the type and magnitude of structural loading. The test specimens were sandwich panels, length 250mm and width 150mm, with carbon fibre prepreg face-sheets ([0°/90°], thickness t f ≅0.5mm) bonded to the faces of a foam core (density 80kg/m3, thickness H =10mm). The impact velocity was approximately 420m/s, using a spherical steel impactor, diameter 10mm, with a mass of 4.1g. A high-speed camera was used for registration of panel response. It was demonstrated, that, at preload levels above a specific limit, the impact would cause catastrophic failure, i.e., complete or near-complete loss of structural load carrying capacity. Developments of failure morphology, consistent with the observed evidence, were derived and outlined. [Copyright &y& Elsevier]