SIMULATION ON THE ELECTRICAL AND MECHANICAL FATIGUE DAMAGE BEHAVIOR OF CONDUCTIVE HYDROGEL INTERFACE UNDER CYCLIC LOADING

In order to study the resistance change of conductive hydrogel patch electrode caused by interface damage under fatigue load, an electrical-mechanical cohesive zone model was proposed in this work. Firstly, based on the viscoelastic mechanical behavior of hydrogel, the Wiechert model was applied to construct the rate-dependent traction-displacement jump relationship of the hydrogel adhesive layer. And the interfacial resistivity was defined as a function of traction force and damage variables. Then, the viscoelastic electrical-mechanical cohesive zone model was numerically implemented by ABAQUS/UEL subroutine. The viscoelastic parameters of the model and the energy release rate of damage initiation and interface fracture of the cohesion model at different strain rates, as well as the variation law of interfacial resistivity with traction force under different loading rates, were determined by shear tests. Afterwards, the effectiveness of the proposed model was verified by a single element simulation. Finally, the model was applied to predict the interfacial resistance growth of the patch electrode adhered by conductive hydrogel under fatigue loading. The results showed that the resistance of the patch electrode presented a fluctuating increase trend with the increment of loading cycles. With the increase of the loading rate, the resistance rising rate gradually decrease, and the resistance fluctuation was smaller. The finite element simulation results were in good agreement with the experiments.