Degeneration character of gels under cyclic loading and its constitutive relation

An interesting degeneration behavior of gel materials under cyclic load is found in experiment. In order to explain this phenomenon, a constitutive mo del is proposed to simulate the microstructure of gels. Further the corresp onding constitutive relation and its simplified form that contains six para meters is proposed to describe the nonlinearity and degeneration of gels un der cyclic loading and unloading. The data of compression experiments for t wo typical gels are simulated by computer. The theoretical results are cons istent with experiments very well.