In-Pane Behavior of Shape Memory Alloy Honeycombs

W. Yang, R. DesRoches, and M. Doyoyo

Honeycombs, one type of cellular materials, have been widely used in modern engineering in applications ranging from light-weight structural sandwich panels to packaging and protective padding.  Under a uniaxial compressive stress, the cell walls in an elastic-plastic cellular material first bend elastic and then collapse due to elastic buckling or plastic yield.  As the deformation is further increased, cell collapse progresses at a roughly constant load, giving a stress plateau and extremely large ductility (60% global strain), until all of the cells have collapsed, leading to a large energy dissipating capacity.  SMA honeycombs not only retain the characteristic honeycomb ability, but also capitalizes on the superelastic effect of SMA material as cell walls, which have not been studied in any previous research.  Numerical models of SMA honeycombs under uniaxial compression loads have been first successfully performed to investigate the effect of thickness-to-length ratio on the post-buckling or post-yielding behavior. [1].  Full-scale experimental program on tests of SMA honeycombs under uniaxial and biaxial compression loads will be conducted to verify the numerical and analytical results.  Furthermore, an analytical model will be derived to predict the plastic collapse strength of SMA honeycombs under in-plane crushing.

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