Data fitting and simulation of hyperelastic and viscoelastic properties of soft tissue

Real deformation modeling of soft tissue is a major difficulty in the development of virtual surgery. The solution of this difficulty requires in-depth research on the mechanical properties of soft tissue. This paper is devoted to the study of constitutive relations in soft tissue mechanical models: viscoelastic model and hyperelastic model. Through a series of experiments and calculations, the stability and applicability of various hyperelastic models were evaluated. The coefficients and exponents of Prony Series in viscoelastic generalized Maxwell model were calculated and optimized. Finally, tensile simulation was carried out based on the existing constitutive model. The results showed that the large intestine soft tissue data fitted by van der Waals model was stable and accurate; The viscoelasticity of large intestine has little influence on the whole stretching process. The viscoelasticity will replace hyperelasticity and dominate the whole stretching process when the viscosity reaches the current 100 times.