A non-linear viscoelastic tensor-mass model for surgery simulation

The linear elastic models of soft tissue are widely used in surgery simulation due to their computation efficiency, however, it is well known that these models are only a coarse approximation of the real properties of biological soft tissue. To achieve realistic simulation, the deformable model should incorporate many other tissue properties such as non-linearity, anisotropy and viscoelasticity. Among these properties, viscoelasticity is a very important one and it determines directly the behaviors of the tissue when it is cut, deformed or torn. In this study, we moved Picinbono's work one step further and proposed to incorporate the property of viscoelasticity into the tissue model. In addition, our model can allow relatively fast computation of the bio-mechanical forces and deformations of soft tissue in simulation. Experiments show that the incorporation of nonlinear viscoelasticity makes the simulated tissue look much more realistic than other models while the computation time is increased by only approximately 5% compared with the original non-linear elastic models. The visual refresh rate can achieve about 40Hz on a regular office computer.