Experimental study on the compression-after-impact behavior of foam-core sandwich panels

This paper presents the experimental results pertaining to the deformation, failure mode, failure mechanism and residual strength for the compression-after-impact tests of woven polymer-based foam-core sandwich panels. Sandwich panels with impact-type damage, inflicted via low-velocity impact, were tested to failure in compression. The optical strain measurement system ARAMIS was used to obtain the complete non-uniform strain and displacement fields of the damaged face-sheet. Consequently, damage in the face-sheets was characterized by fractography. It has been found that the dominant damage mechanism is kink band in the impacted face-sheets due to fiber plastic micro-buckling. Besides, the effects of impactor diameter, impact energy, face-sheet thickness and foam core thickness on the residual strength under in-plane compressive loading were studied. This study will be useful for characterizing and predicting the residual compressive strength and understanding the failure mechanism of woven polymer-based foam-core sandwich panel.