Viscoelastic characterization of soft tissue from dynamic finite element models
Viscoelastic characterization of soft tissue from dynamic finite element models
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DOI：
10.1088/0031-9155/53/22/018
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发表时间：
2008-11-21
影响因子：
3.5
通讯作者：
Ohayon, Jacques
中科院分区：
文献类型：
--
作者：
Eskandari, Hani;Salcudean, Septimiu E.;Ohayon, Jacques
本文提出了弹性和粘性反问题的一种迭代解法。建立了一种新的动态有限元模型，该模型与已有的流变模型一致，可以考虑软组织的粘弹性变化。该模型假定节点处的集中质量已知，并包括两个分别取决于材料弹性和粘性分布的弹性和粘性参数矢量。利用该变形模型和简谐激励下的观测动力学数据，用基于高斯-牛顿的方法求解了反问题，重建了介质中的粘性和弹性。正如在其他反问题中一样，为了确保唯一性和收敛以及获得粘弹性性质的准确映射，必须事先知道介质边界上的参数。通过数值模拟研究了解对噪声、模型和边界条件的敏感性。给出了实验结果。含有已知性质包裹体的明胶模体的粘度和弹性已被重建，并已被证明接近于使用标准流变仪获得的值。
An iterative solution to the inverse problem of elasticity and viscosity is proposed in this paper. A new dynamic finite element model that is consistent with known rheological models has been derived to account for the viscoelastic changes in soft tissue. The model assumes known lumped masses at the nodes, and comprises two vectors of elasticity and viscosity parameters that depend on the material elasticity and viscosity distribution, respectively. Using this deformation model and the observed dynamic data for harmonic excitation, the inverse problem is solved to reconstruct the viscosity and elasticity in the medium by using a Gauss-Newton-based approach. As in other inverse problems, previous knowledge of the parameters on the boundaries of the medium is necessary to assure uniqueness and convergence and to obtain an accurate map of the viscoelastic properties. The sensitivity of the solutions to noise, model and boundary conditions has been studied through numerical simulations. Experimental results are also presented. The viscosity and elasticity of a gelatin-based phantom with inclusion of known properties have been reconstructed and have been shown to be close to the values obtained using standard rheometry.