Lagrangian finite element treatment of transient vibration/acoustics of biosolids immersed in fluids
Lagrangian finite element treatment of transient vibration/acoustics of biosolids immersed in fluids
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DOI：
10.1002/nme.2192
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发表时间：
2008-04-30
影响因子：
2.9
通讯作者：
Hildebrand, J. A.
中科院分区：
文献类型：
--
作者：
Krysl, P.;Cranford, T. W.;Hildebrand, J. A.
在基于位移的有限元模型中，利用叠加原理将入射声波与散射波和辐射波分离。将吸收边界条件应用于位移的摄动部分。线性本构方程允许非均匀的、各向异性的材料，包括流体和固体。计算体中的所有材料均采用基于位移的有限元。对于压缩系数有限的材料，采用假定应变节点集成的单纯形单元或不相容模式的砖单元可以获得较好的性能。为了准确、高效地处理一般的阻尼问题，提出了一种中心差分时间步长算法。讨论了假定应变单纯形和基于体素的砖有限元模型的验证问题(浸没在水中的空钢柱对阶跃平面波的响应，以及弹性球体对简谐平面波的散射)。描述了一种基于体素的复杂生物几何建模方案，并从生物声学应用领域给出了两个说明性的结果：人耳接收声音和模拟喙鲸的生物声纳。版权所有(C)2007 John Wiley&Sons，Ltd.
Superposition principle is used to separate the incident acoustic wave from the scattered and radiated waves in a displacement-based finite element model. An absorbing boundary condition is applied to the perturbation part of the displacement. Linear constitutive equation allows for inhomogeneous, anisotropic materials, both fluids and solids. Displacement-based finite elements are used for all materials in the computational volume. Robust performance for materials with limited compressibility is achieved using assumed-strain nodally integrated simplex elements or incompatible-mode brick elements. A centered-difference time-stepping algorithm is formulated to handle general damping accurately and efficiently. Verification problems (response of empty steel cylinder immersed in water to a step plane wave, and scattering of harmonic plane waves from an elastic sphere) are discussed for assumed-strain simplex and for voxel-based brick finite element models. A voxel-based modeling scheme for complex biological geometries is described, and two illustrative results are presented from the bioacoustics application domain: reception of sound by the human ear and simulation of biosonar in beaked whales. Copyright (c) 2007 John Wiley & Sons, Ltd.