Numerical modelling of Nomex honeycomb sandwich cores at meso-scale level

Experimental and numerical analysis of the shear nonlinear behaviour of Nomex honeycomb core: Application to insert sizing

“…5-b). This effect could have been avoided by adding articulations at each end of the specimen as was done by Seemann et al [4] but this would have added some complexity to the fabrication procedure and test setup.…”

“…In fact, there are also studies on the nonlinear shear behavior of honeycombs by authors interested in the pull-out of inserts in sandwich structures [4], and this is also what motivated the present study. Bunyawanichakul et al [5,6] propose a nonlinear model of highly loaded inserts that take the nonlinear honeycomb response, the nonlinear potting behaviour and the punching failure of the CFRP laminate skins into account.…”

“…This means that the two honeycomb cores may show different structural behaviour and thus different failure scenarios. Similarly, the nonlinear shear behavior varies according to the authors; for example, the differences between the results obtained by Bunywanichakul et al [5,6] and by Seeman and Krause [4] deserve to be explained. Finally, although many authors identify the shear buckling of honeycomb cells perfectly, no author has raised the question of the reversibility of postbuckling to date.…”

“…Most of the core used, e.g. for cabin interiors or landing gear doors, is made of Nomex honeycomb [4][5][6][7]. It is well known that, when a sandwich is subjected to a bending load, the core absorbs almost all the shear components of the force.…”

“…However, the results depend on good determination of the material characteristics of the impregnated aramid paper used [32] and on whether the local geometry is properly taken into account. Seemann and Krause [4] have proposed a very detailed model of Nomex honeycomb that exhaustively considers the honeycomb defects and mesostructure and is able to model the nonlinear shear response with a rail shear test.…”