DIC Analysis On Strain Distribution And The Research On Electromechanical Coupling Model Of IPMC

IPMC is a kind of electroactive polymers,it has broad application prospects in robotics,aerospace and other fields.Real strain response,which can reveal the relationship between deformation and motivation,is the basis of modeling and engineering application.However,traditional strain test technique is not applicable to IPMC.This paper introduced DIC technique into mesoscopic deformation test and analysis of Pt-IPMC,and the electromechanical coupling model were studied combined with the basic mechanical,electrical and deformation characteristics of IPMC.In this paper,the representation of Pt-IPMC's structure properties,mechanical/electrical parameters and driving performance was conducted.The water content,tensile properties,surface resistance and interelectrode electrical parameters were obtained.The nonlinear deformation features and the size effect of IPMC was also tested.The displacement/strain response testing system was set up.By controlling the excitation voltage/frequency,transverse and longitudinal section location,driving time respectively,the distribution rule of displacement and strain was analyzed.Further,the distribution rule of principal strain,longitudinal and transverse normal strain was analyzed.According to the results,there exists strain gradient in bending of IPMC,and the strain gradient increased linearly with excitation voltage.In addition,the experimental errors of DIC method were analyzed in detail,and the suitable experimental parameters were chosen.By introducing DIC test result as electromechanical coupling relationship into distributed electrical model,the electromechanical coupling model was proposed.As layered composite material,the stress of IPMC on the cross section distributed uncontinuously,but the deformation and strain have continuous distribution.This model was based on strain relationship and not involving discontinuous strain relations,which can well simulate the nonlinear deformation behavior of IPMC.The comparison between measured and calculated values of displacement shows that the error of the model is less than 10%.