In order to study the creep viscoelastic constitutive relation model of polyimide film,with a thickness of 25 μm was selected,and the initial stress was 50%of the ultimate tensile strength.The uniax-ial creep tensile test was carried out at six temperatures of 23,50,80,110,140 and 170℃,and the creep variation of the film at different temperatures was analyzed.Five creep constitutive models of classical Kelvin,classical Maxwell,Burgers,three-parameter generalized Kelvin and five-parameter generalized Kelvin were used to fit the experimental data,and the fitting effects of each model compared and ana-lyzed.The results showed that the polyimide membrane had obvious viscoelastic properties.The initial stress had a significant effect on the creep properties of the polyimide membrane.The greater the initial stress,the more obvious the viscoelasticity.The five-parameter generalized Kelvin model could well pre-dict the creep properties of the membrane,and the coefficient of determination was more than 0.98.The Burgers model was followed and the fitting coefficients of other models were between 0.708 and 0.958.The fitting results could meet the needs of practical engineering.
polyimide filmviscoelastic mechaniccreep performancecreep constitutive model
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