Quantifying non-linear effects in high-rate elastic recoil

A quantitative understanding of the mechanical properties of materials unloading at high rates and large deformations is important for the design of elastic mechanisms to drive ultra-fast movements. Recoil testing is a direct way to measure unloading performance, where high speed videography is used to track the displacement field of a freely retracting material. However, current approaches to recoil testing do not consider non-linear viscoelastic properties of materials during retraction from large deformations. In our work, we combine experimental recoil measurements with viscoelastic wave propagation simulations. As a first step, we find agreement between our experiment and simulation for key metrics of kinematic performance such as maximum power output during retraction as initial strain in the material is increased.