Strength Variability of Inserts in Sandwich Panels

Abstract

Bonded inserts are commonly used to introduce localized loads into sandwich panels. This article investigates sources of variability in the pull-out strength of metallic inserts in aramid honeycomb sandwich panels. Finite element modeling is used to investigate the sensitivity of core stresses to potting depth in partially potted inserts, which is found to be significant. Experimental specimens showed large variations in potting radii and cell wall dimensions, both critical parameters since the failure mode is predominantly core shear, adjacent to the potting. Foam core specimens were also tested and showed significantly lower variability in pull-out strength compared with honeycomb specimens.