Energy absorption of sandwiched honeycombs with facesheets under in-plane crushing

Abstract

AbstractThe in-plane crushing and energy absorption of sandwiched honeycomb cores with facesheets are examined through finite element simulations. Assuming no debonding between the facesheet and honeycomb core (which would be the case if manufacturing techniques such as brazing are used to produce very strong bonds between the facesheeet and the core), intracellular buckling mode for thin facesheets, and wrinkling mode for thick facesheets are observed. In the dimpling mode, deformation is governed by the core, honeycomb vertical cell walls do not deform, and the inclined wall deformation does not vary through the cell depth. In the wrinkling mode, deformation is governed by the facesheet, the vertical cell walls deform significantly, and the inclined cell wall deformation varies through the cell depth. Increasing cell angle increased Specific Energy Absorption (SEA) for honeycombs with thin facesheets. Decreasing vertical cell wall length increased SEA for honeycombs with thick facesheets. Increasing wall thickness and decreasing core depth increased SEA for honeycombs with thin and thick facesheets. With geometric changes, SEA increased ~3 times over the baseline configurations. For a given keel beam dimensions, using fewer rows of larger cells reduces the effective non-dimensional core-depth, thereby increasing the effect of the facesheet and the SEA significantly. The SEA of sandwiched honeycombs with facesheets in in-plane crushing appears to be competitive with, or better than, SEA honeycombs in out-of-plane crushing.