Mesh Generation Of Hip Model And Program Implementation

Solid mesh is the main object of operation motion simulation and human tissue deformation calculation in virtual surgery system.In the process of hip model simplification and mesh division,great changes of topology location have a significant impact on the authenticity,accuracy and efficiency of surgical simulation.So it's urgent for the research of high quality mesh and geometric precision.Edge collapse algorithm based on Quadratic Error Metric is used to simply the model.Combination of AFT algorithm and Delaunay algorithm is used to generate mesh model.Firstly,completion of simplified operation.Fold cost function is improved by the adjacent area of a triangle.Then arrange the edge of model.Judge the legality of the edge of minimum folding cost,calculate new vertex position and update topology.Recalculate new edge collapse cost and reorder.Select cost smallest folding edge to collapse operation,until the rest specify another number of the simplified operation model.This article effectively ensures the accuracy of the simplified model geometry through the improvement of the fold cost function.Using algorithm in this paper for multi-resolution simplification of hip model experiment,good geometric accuracy is gained.And it also lays a foundation for meshing.Secondly,mesh generation of hip model.Hip model is the discrete surface model with complex boundaries,unconspicuous contours and more features.Identify sub-domain and reconstruct surface,establish comprehensive size field and discrete sub-domain boundary.AFT algorithm is used to generate surface mesh.And geometric accuracy is maintained by the local coordinate conversion and local mesh refinement.With the input of surface mesh,Waston-Bowyer point-wise insertion method is used to complete the hips internal Delaunay tetrahedron grid division and optimization.Through experiments for different size mesh division of simplified hip model using this algorithm,it's obvious that the algorithm successfully maintains the geometric accuracy and generated high-quality mesh.Finally,verification of hip mesh models.The algorithm is used to simplify femur model and generate mesh model.Then the mesh model is imported in Abaqus Software.Through finite element analysis,the strain datum of 8 test-points under the load of 100N,400N and 800N are gained.Through comparison and analysis of calculation and experimental datum as well as cloud contour,the mesh results gained by the algorithm own ideal shape,gentle transition and good geometric accuracy.Therefore,the algorithm can better meet the requirements of practical engineering application in virtual surgery system.