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arXiv 1105.0455math.NAcs.NAmath-phmath.MP
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几乎不可压缩材料中弹性波动方程的边界估计

Boundary estimates for the elastic wave equation in almost incompressible materials

Träskö-Storö Institute of Mathematics, Stockholm, Sweden(斯德哥尔摩特拉斯科-斯托罗数学研究所);Center for Applied Scientific Computing, Lawrence Livermore National Laboratory(劳伦斯利弗莫尔国家实验室应用科学计算中心)

Heinz-Otto Kreiss, N. Anders Petersson

AI总结:

针对几乎不可压缩材料,通过简正模态分析建立弹性波动方程在自由表面边界条件下的边界稳定性估计,揭示材料参数对数值离散误差的影响,并推导出为保持瑞利面波相速度精度所需的网格尺寸缩放律。

摘要:

我们研究了自由表面边界条件下弹性波动方程的半平面问题,特别关注几乎不可压缩材料。发展了简正模态分析,根据边界数据估计解,表明问题是边界稳定的。我们的估计使材料属性的依赖性变得透明,而能量法难以分析这种依赖性。简正模态技术用于分析有限差分近似中截断误差的影响。我们的分析解释了为什么当剪切模量($\mu$)变小时,即对于几乎不可压缩材料,必须增加每波长的网格点数。为了在$\mu\to 0$时获得瑞利表面波相速度的固定误差,我们的分析预测,对于二阶方法,网格尺寸必须与$\mu^{1/2}$成正比。对于四阶方法,网格尺寸可以与$\mu^{1/4}$成正比。数值实验证实了这一缩放律,并展示了四阶方法的优越效率。

英文摘要:

We study the half-plane problem for the elastic wave equation subject to a free surface boundary condition, with particular emphasis on almost incompressible materials. A normal mode analysis is developed to estimate the solution in terms of the boundary data, showing that the problem is boundary stable. The dependence on the material properties, which is difficult to analyze by the energy method, is made transparent by our estimates. The normal mode technique is used to analyze the influence of truncation errors in a finite difference approximation. Our analysis explains why the number of grid points per wave length must be increased when the shear modulus ($μ$) becomes small, that is, for almost incompressible materials. To obtain a fixed error in the phase velocity of Rayleigh surface waves as $μ\to 0$, our analysis predicts that the grid size must be proportional to $μ^{1/2}$ for a second order method. For a fourth order method, the grid size can be proportional to $μ^{1/4}$. Numerical experiments confirm this scaling and illustrate the superior efficiency of the fourth order method.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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