Abstract

Stretchy tissues like tendons are used as biological springs for tasks like locomotion and projectile launch. We model these as 1-dimensional viscoelastic materials. We present two methods for simulating their recoil, one based on differential equations and one based on the hereditary integral. Using the simulations, we probe how various parameters can impact two performance metrics: energy efficiency and power output. Among the results are that for low to medium load masses, energy efficiency scales linearly with E₀/E_∞, a measure of the importance of viscous behavior relative to elastic behavior of the spring material, where E₀ is the instantaneous and E_∞ is the long-time modulus response. Power scales quadratically with this ratio. Additionally, we lay out how these results can be used to provide more fair comparisons of mechanisms which are very different in scale.