Mechanical Behavior of Bio-inspired Sandwich Composites

Nature is a popular source of inspiration for the development of new materials and structures. Palmetto wood has been found to be a potential bio-inspiration due to its historically successful mechanical performance to develop materials with enhanced mechanical properties. To understand the basis of mechanical performance of Palmetto wood, its failure mechanism and energy absorbing capacity is elucidated at multiple length scales. The quasi-static and dynamic three-point bend tests has been used to reveal the leading failure mechanisms like shear dominated debonding and pore collapse. The damage evolution under quasi-static and dynamic impact is determined. The sandwich material systems are yet to be investigated in detail to utilize its potential in advanced engineering applications. We present some work on development of sandwich composites with improved mechanical behavior using Palmetto wood as a biological template. The quasi-static and dynamic characterization of nano-enhanced sandwich materials is presented. The leading failure mechanism in Palmetto wood are found to be shear dominated delamination at the macrofiber-matrix interface caused by shear strain concentration and shear cracking in the porous cellulose matrix caused by pore collapse. Reinforcement in the bio-inspired core and the nano-enhancement in the adhesive increase the mechanical properties of the sandwich structure.