A novel bio-inspired microstructure for improved compressive performance of multidirectional CFRP laminates

Abstract

In this work, we design, manufacture, test and discuss the first bio-inspired microstructural concept to enhance longitudinal compressive performance of multidirectional (MD) Carbon Fibre Reinforced Polymer (CFRP) laminates. To do so, we take inspiration from biologically occurring layered materials; one remarkable example being the anchoring spicula of the deep-sea glass sponge Monoraphis chuni. We designed numerically various concepts and then devised a strategy to reproduce, in a MD CFRP laminate, the characteristic alternation of stiff and soft regions observed in this material, followed by a bespoke procedure to manufacture the laminate. We evaluated their performances by means of small-scale notched compression tests and direct comparison with an industrially relevant baseline laminate. Our results show that the proposed concept led to a statistically significant increase in the failure load and in the average ligament specific stress at failure. Furthermore, the designed microstructure showed potential to delay damage initiation from a stress concentration and to arrest damage propagation. We conclude that the presented microstructural concept is potentially of great value for the design of lightweight structures undergoing compression loading.