Processing and high strain rate impact response of multi-functional sandwich composites

Sandwich composites are finding increasing applications in aerospace, marine and commercial structures because they offer high bending stiffness and lightweight advantages. Currently, foam and honeycomb core sandwich composites are widely used in structural applications. However, affordability continues to be the driver to develop sandwich constructions that can be processed at lower costs and containing integrated design features. This paper considers sandwich constructions with reinforced cores by way of three-dimensional Z-pins embedded into foam, honeycomb cells filled with foam, and hollow/space accessible Z-pins acting as core reinforcement. These designs offer added advantages over conventional constructions load bearing by enabling functions such as ability to route wires, mount electronic components, increase transverse stiffness, tailor vibration damping, etc. With the assumption that these sandwich constructions would be part of a larger structure, impact damage is often of concern. This paper deals with: (a) processing of sandwich composites using out-of-autoclave cost-effective liquid molding approach, and (b) investigation of the high strain rate impact (164–326/s) response of the sandwich composite structures. Wherever applicable, comparisons are made to traditional foam core and honeycomb core sandwich constructions.