Impact Behaviour of Sandwich Panels Made of Flax Fiber-Reinforced Bio-Based Polymer Face Sheets and Foam Cores

In this paper, the impact behaviour of sandwich panels constructed of flax fibre-reinforced polymer (FFRP) facings and closed cell polyisocyanurate foam cores is studied. A total of 27 sandwich beam specimens (1200 mm long and 150 mm wide) made of 75 mm thick foam have been fabricated. As a part of this study, three of these specimens have been tested under impact load at several energy levels. The main test parameter is the facing thickness (one, two, or three layers of FFRP). A bidirectional flax fabric (400 g/m(2)) was used for the face sheets and a foam with a density of 64 kg/m(3) was used for the core. A bio-based epoxy resin, with an approximate bio-content of 30%, was used to make the FRP facings. Each specimen was tested multiple times increasing the kinetic energy until failure. The kinetic energy was increased by first increasing the drop height and then, if necessary, adding additional weight to the impactor and resetting the height to keep the increase in energy constant. The acceleration of the impactor, the drop weight velocity, and the top and bottom facing strains at mid-span will be measured. It is expected that ultimate energy absorption and strength of the specimens will increase as both the core density and facing thickness increase. The aim of this paper is to provide data to the field of study, provide insight into the structural behavior of these types of structures, and show their viability for use in infrastructure. With further research, there is the potential that these types of structures could be included in structural building codes. This research is part of a larger on-going study and more results will be available at the time of the conference.