Failure of Sandwich to Laminate Tapered Composite Structures

Failure modes and load distributions in tapered, minimum-gauge composite sandwich structures were investigated. A total of 36 unidirectional graphite-epoxy/Rohacell foamcore structures were manufactured with varying taper angles and core thicknesses. The specimens were subjected to tensile, compressive, and bending loads. Experimental data were correlated with a three-dimensional e nite element model developed to determine the stress and the strain state within a tapered sandwich structure. Emphasis was placed on the root of the taper, where experimental observations suggested damage initiation.