Modeling elastic, viscous and creep characteristics of cellulose Electro-Active Paper

A mechanical model of the elastic, viscous and creep behavior of a cellulose-based Electro-Active Paper (EAPap), including C1, C2, and C6 along three material axes is developed and verified. The model consists of a spring-dashpot system that predicts the response under cyclic loading as a function of temperature. The modeling system providing the most consistent results consists of a spring and dashpot in parallel with each other, both in series with another dashpot. While the spring and dashpot in parallel represents both elastic and viscous response delay, the series dashpot accounts for the higher creep rates associated with elevated temperatures. The three parameters of this model are determined by fitting experimental data to the mathematical solution under cyclic loading conditions through a nonlinear least-squares method. There are a number of complex nonlinear load displacement mechanisms involved in the initial load cycle, thus to minimize modeling errors, most of the simulation modeling was developed to predict the mature portion of the load deflection curve through failure.The results presented in these studies strongly suggest that this three-parameter accurately describes the response of the three electroactive papers studied. The material creeps at elevated temperature, but there is insignificant creep at room temperature. The elastic behavior varies inversely with temperature and with the bias angle tested; however, the overall viscous behavior of the three types of EAPap tested is relatively complex.