Visco-hyperelastic material modeling using nested linkage mechanisms

In this study, basic linear lumped elements such as springs and dashpots are used in nested linkage mechanisms in order to simulate the mechanical behavior of visco-hyperelastic materials. The proposed mechanism model containing two nested linkages can show initial softening followed by hardening response under quasi-static loading, which is commonly displayed by hyperelastic materials. Hence, material nonlinearity is simulated by geometric nonlinearity of the linkage mechanism. The mechanism also displays relaxation, hysteresis, and dynamic stiffness responses of viscoelastic materials with the help of dashpot elements. Visco-hyperelastic material behavior is closely approximated by the proposed mechanism model for the four different test scenarios, i.e., quasi-static loading, ramp-and-hold loading, hysteresis, and dynamic stiffness tests. It is shown that nonlinearity and frequency dependency of viscohyperelastic materials is successfully captured. (C) 2020 Elsevier Ltd. All rights reserved.