A K-shaped spring configuration to boost elastic potential energy

In this paper, a nonlinear elastic system is presented to increase the elastic potential energy for storage and release. The system consists of four linear mechanical springs arranged in a K-shaped configuration to achieve a specific form of nonlinearity. The arrangement is inspired by the interaction among the filaments of protein in the sarcomere, which is the fundamental unit of the skeletal muscles. Similarly to the sarcomere, where synergy is exploited from active and passive components, a bi-stable system is coupled to a hardening one, and an insight is provided for design and optimization. The theoretical formulation is validated through numerical simulations and experimental results. The insight provided could be exploited in the conception of advanced bio-inspired structures, materials and actuators to effectively store and release energy.