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| Soft Tissue Modeling Based on MLS-MWS Mixing Method |
| Chen Weidong1,2 Liu Bo1 Zhu Qiguang1,2* |
1 Insitute of Information Science and Engineering, Yanshan University, Qinhuangdao 066004,China
2 The Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province, Qinhuangdao 066004,China |
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Abstract Targeting to problem of the large computation amount of mesh-free model and tedious boundary processing, MLS-MWS based on the improved least square approximation was proposed in this work. At first, the model was divided into the internal domain and external domain based on the field theory. In the internal domain, nodes far from the natural boundary constructed the equation of equilibrium with the mesh-free method. The method has no numerical integration, which may reduce the computation amount. In the external domain, the boundary problem was weakened through the mesh-free partial weak method. Secondly in the strong method, second-order derivative of the displacement should be indicated with the least square approximation equation. Targeting tothe large computation amount of mesh-free model and low efficiency, it was proposed to improve the moving least square approximation function and derivate, and MLS derivative interpolation was carried out for the node value, for working out the second-order derivative and further simplifying the computation. Eventually, deformation simulation experiment of stretching and squeezing the liver model was carried out with the PHANTOM touch interactive equipment. According to the results, the single-step execution time of MLS-MWS combined model was reduced to 13.8 ms from the original 17.3 ms of the mesh-free model, while the frequency was improved from 56.80 frames/s to 72.46 frames/s. The mixed model integrated advantages of the mesh-free weak-strong method and dual mesh-free point-allotting method, which improved the instantaneity of the model effectively.
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Received: 12 January 2016
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