Smart tetrachiral and hexachiral honeycomb: Sensing and impact detection

In this work we present concepts and prototypes of a novel class of chiral honeycomb core with embedded sensing characteristics for potential structural health monitoring (SHM) and other multifunctional applications. The cellular structure concepts, all having negative Poisson's ratio behaviour, have piezoelectric sensors and their hardware support embedded on the surface, or within the unit cell plates. Both the sensors and the infrastructure provide not only the capability of detecting signals proportional to the external mechanical loading, but act also as load-bearing units. The honeycombs have been produced using vacuum-casting techniques and resin transfer moulding methods, with micro fibre composites (MFCs) embedded in their cell walls. The sensing and mechanical performance of the prototypes are evaluated using finite element simulations, static tests, broadband vibration excitation and impact at low kinetic energy levels using an airgun.