Energy absorption of muscle-inspired hierarchical structure: Experimental investigation

Muscles act as a cushioning layer protecting most of our brittle bones and delicate visceral organs. Inspired by the internal architecture of skeletal muscle tissues, a novel tubular section design with structural hierarchy was recently proposed for impact protection (Tsang and Raza, 2018). This paper presents a fundamental experimental investigation of the force resistance and energy absorption capabilities of the proposed hierarchical structure. A soft and ductile thermoplastic polyurethane (TPU) with Shore-A hardness of 95 is used for three-dimensional (3D) printing of the specimens. The enhanced force resistance and energy absorption are then quantified based on the hysteretic behaviour observed in a series of quasi-static compression tests with loading and unloading. The superior force resistance and energy absorption capabilities of the muscle-inspired hierarchical structure are proven.