Modeling and parameter identification of rheological object based on FE method and nonlinear optimization

There are many kinds of deformable objects in our living life. Some of them such as human tissues, human organs, and food exhibit rheological behaviors when they are subject to external force. In surgery simulation and food engineering, we need to simulate or control such behaviors. In this paper, four-element model associated with finite element (FE) method was employed to model rheological deformation. This model can reach a good approximation of rheological force response when the object experience a standard strain input. An identification approach for estimating physical parameters of rheological deformation was presented based on 2D FE simulation and nonlinear optimization. This identification method aimed at minimizing the difference of force response between the simulation and experiment by using nonlinear least square method. Finally, experiments and identification results were given and both modeling and identification method were validated by comparing the results of simulation and experiments.