Assignment and verification on mechanical parameters of soft tissue in finite element analysis

Objective: To obtain an optimized method of providing hyperelastic parameters of soft tissue, and to promote the simulation accuracy in explicit solution of finite element analysis (FEA) on soft tissue impact test. Methods: Compressive properties of soft tissue from six fresh planta were measured. The experimental data were used to calculate the FEA material properties, which were then optimized by Poisson's ratio. With the same loading and boundary conditions as the experiment, the FEA model was conducted for simulation. The simulation results were verified by both the experimental data and literature data. Results: The force-displacement curve of soft tissue presented an exponential growth trend in the in vitro biomechanical experiment. When the compression ratio was under 45%, the FEA simulation result was consistent with the experimental data. When the compression ratio was above 45%, the closer the Poisson's ratio up to 0.5, the higher the accuracy of FEA simulation result. However, there was a strong linear correlation between the FEA simulation results and experimental data (R2=0.9923) when the Poisson's ratio was 0.497. Conclusions: The simulation result of material parameters in FEA model is preferable in this study. With a lower compression ratio, the simulation results from FEA model are in consistency with the experimental data. Increasing the Poisson's ratio can promote the simulation accuracy of the FEA model when the compression ratio is high.