Numerical study of composite sandwich panels with compound cellular core of auxetic lattice structure and foam under low velocity impact load.

Updated standards in safety of vehicles and related facilities have led to use of smart designs and advanced manufacturing techniques. The shock generated at impacts could cause serious damages both to the system’s structure and the human body. A conventional method used to reduce the impact shock is to employ cellular material, e.g. low density foams in forms of sandwich structures. In the present work, performance of fiberglass-epoxy composite panels with Expanded Polystyrene (EPS) foam core under low velocity impact is enhanced by employing ۳D printable lattice structure inside the sandwich panel. Lattice structure is designed based on re-entrant auxetic pattern and it is manufactured using ABS material. Tests are conducted numerically using LS-DYNA explicit code at two different impact speeds. Results are discussed based on rigid body acceleration of the impactor to investigate the effect of adding auxetic structure on the shock attenuation. Furthermore, core arrangement of upgraded specimen is changed in three different ways are results are presented.

Keywords:

Composite sandwich panel , FE simulation , fiberglass-epoxy , cellular material , auxetic structure