Finite-element Simulation of Seismic Ground Motion with a Voxel Mesh
Finite-element Simulation of Seismic Ground Motion with a Voxel Mesh
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DOI：
10.1007/978-3-0348-7875-3_6
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发表时间：
2004-12
影响因子：
2
通讯作者：
K. Koketsu;H. Fujiwara;Y. Ikegami
中科院分区：
文献类型：
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作者：
K. Koketsu;H. Fujiwara;Y. Ikegami
精确模拟三维复杂地形和结构的地震地面运动是强震地震学最重要的目标之一。有限元法（FEM）非常适合这种模拟，因为公式中已经包含了无牵引力条件，而且Courant条件没有有限差分法（FDM）严格。然而，有限元法通常需要大量的内存和计算时间。这些限制可以通过使用由体素（矩形棱镜）组成的网格来克服，各向同性内建于动态矩阵方程的显式公式中。由于体素有限元中的算子是普通FDM算子和附加项的组合，该方法保持了与FDM相同数量级的精度，且附加项放宽了Courant条件。体素FEM需要相似的内存量，并且只需要1.2 ~ 1.4倍的计算时间。体素网格的生成速度比流行的四面体网格快得多。由点或线源引起的地面运动和静态位移都可以用体素有限元方法计算。通过与反射率法和理论解的比较，证明了该方法的成功实施，然后将其应用于更复杂的问题。
— Accurate simulation of seismic ground motion for three-dimensionally complex topography and structures is one of the most important goals of strong motion seismology. The finite-element method (FEM) is well suited for this kind of simulation, since traction-free conditions are already included in the formulation, and the Courant condition is less strict than for the finite-difference method (FDM). However, the FEM usually requires both large memory and computation time. These limitations can be overcome by using a mesh consisting of voxels (rectangular prisms) with isotropy built into the explicit formulation of the dynamic matrix equation. Since operators in the voxel FEM are the combinations of ordinary FDM operators and additional terms, the method keeps accuracy of the same order as FDM and the terms relax the Courant condition. The voxel FEM requires a similar amount of memory and only takes 1.2∼1.4 times longer computation time. The voxel mesh can be generated considerably faster than the popular tetrahedral mesh. Both ground motions and static displacements due to a point or line source can be calculated using the voxel FEM approach. Comparisons with the reflectivity method and theoretical solutions demonstrate the successful implementation of the method, which is then applied to more complex problems.