Research Projects

In the aerospace/automobile industries, composites are widely used due to their lightweight characteristics, high stiffness, and strength. Protecting such structures against low-velocity impact is of particular interest since it can induce barely visible impact damage (BVID). One way to protect against low-velocity impacts is through the use of sandwich panels with an impact-resistant core material. Notably, sandwich composite structures, using carbon fiber/epoxy resin (CFRP) composites as the stiffer skin with low-density honeycomb or foam cores, serve as an ideal configuration for light-weight structural components resisting impact. Delamination is the major mode of failure in CFRP laminates developed using conventional 2D fabrics. 3D woven fabric composites have demonstrated their potential to eliminate the problem of delamination due to presence of fiber in the z-direction. Cenosphere is low density material extracted from fly ash, which is a waste product obtained from industries and harmful to environment. Inclusion of cenosphere results in reduced density, enhanced compressive strength and improved impact resistance. Recently, Auxetic composites are being explored in defence and aerospace applications, owing to its superior mechanical properties. Contrary to convention materials, when Auxetic composites are subjected to an impact force, material flow into the impact point. This facilitates high energy absorption, indentation resistance and act as good buffers for impact loads. Alongside, several significant attempts have been made to develop Auxetic laminates and yarns. But minimal attention has been paid to develop and investigate 3D Auxetic composites. Poly-ether-ether-ketone (PEEK) matrix composites have recently grasped the attention of the researchers due to its high performance in contrast to the existing matrix materials. To this end, the investigators have decided to incorporate additive manufacturing process to develop impact resistant sandwich composite comprising of CFRP facesheet along with novel 3D printed cenosphere reinforced PEEK core. Thus developed sandwich composites will be assessed for their energy absorption and damage mitigation behaviour by subjecting them to low velocity impact test using drop weight impact testing machine. In this context, the current proposal takes a hybrid approach, not explored previously, to develop impact-resistant sandwich composites by: (1) harnessing the Auxeticity to achieve a lightweight, yet effective energy-absorbing core and (2) employ industrial waste fly ash facilitating sustainable composite development through both experimental and computational approach. It is believed that the present study serves as a motivation for make in India concept for developing the various impact resistant products such as bumpers for automobiles and various structural components for aerospace application with reduced areal density.