Soft-tissue-Meshfree-model

Global Meshfree model

Meshless Model (MM) can simulate large deformations of soft tissue. MM are classified by the type of shape function used: Moving least square method (MLS) shape functions, integral form shape functions, and point interpolation method (PIM) shape functions. Applying the MLS method, Xu Shaojian introduced a viscoelastic model of the liver to make it closer to bio-mechanical properties of liver soft tissue and performed collision detection experiments on the model. According to the results, the meshless method is mathematically simple, presents a good sense of deformation, and represents a significant advance in the modeling of soft tissue deformation during virtual surgery. Zhu and Yu established a mathematical model of liver and stomach surface by using a modification of MLS, Element Free Galerkin (EFG). EFG eliminates FEM’s greatest source of inaccuracy: the inability to analyze large deformations. However, MM methods require careful choice of underlying mathematical model in simulating human soft tissue as equations that do not fit the boundary conditions usually have no solution.