In this paper, the scattering of elastic waves by a plane interface crack in Layered media is investigated. By Fourier integral transform, the method of transfer matrix is extended to the scattering of elastic waves b...In this paper, the scattering of elastic waves by a plane interface crack in Layered media is investigated. By Fourier integral transform, the method of transfer matrix is extended to the scattering of elastic waves by a plane interface crack in layered media, and the problems are reduced to a set of dual integral equations in matrix form. As an example, the far field modes of scattering of elastic waves by a plane interface crack in a layered half space have been presented. Amplitudes in far field modes are plotted versus incident wave frequency for several groups of different material combinations, and the numerical results show that resonance peaks occur at some frequencies. The frequencies at which the resonanse peaks occur for P and SV waves are almost the same.展开更多
The method of reverberation-ray matrix （MRRM） is extended and modified for the analysis of free wave propagation in anisotropic layered elastic media. A general, numerically stable formulation is established within ...The method of reverberation-ray matrix （MRRM） is extended and modified for the analysis of free wave propagation in anisotropic layered elastic media. A general, numerically stable formulation is established within the state space framework. The compatibility of physical variables in local dual coordinates gives the phase relation, from which exponentially growing functions are excluded. The interface and boundary conditions lead to the scattering relation, which avoids matrix inversion operation. Numerical examples are given to show the high accuracy of the present MRRM.展开更多
从TTI介质一阶应力—速度方程出发,利用旋转交错网格高阶有限差分方法,将非分裂完全匹配层(Non-spliting Perfect Match Layer,简称NPML)边界吸收条件和自由边界条件相结合形成组合边界条件,进行了二维三分量TTI介质弹性波场数值模拟。...从TTI介质一阶应力—速度方程出发,利用旋转交错网格高阶有限差分方法,将非分裂完全匹配层(Non-spliting Perfect Match Layer,简称NPML)边界吸收条件和自由边界条件相结合形成组合边界条件,进行了二维三分量TTI介质弹性波场数值模拟。波场快照和炮记录表明:①采用非分裂式边界条件能较好地消除近地表大角度入射波和瞬逝波;②组合边界条件与NPML边界吸收条件相比,不仅有效地压制了边界反射,同时实现了对自由地表的模拟,获得了丰富的全波场信息,其中在地表产生的PS转换横波作为一种特殊的横波现象,可为近地表结构调查以及多波波场分析等提供有益信息;③自由地表引起的面波以及多次波对偏移结果有着重要影响,因此在实际地震资料处理中应当充分考虑自由地表条件对波场的影响效应。数值模拟结果证实了组合边界条件下二维三分量TTI介质波场数值模拟方法的可行性和正确性。展开更多
文摘In this paper, the scattering of elastic waves by a plane interface crack in Layered media is investigated. By Fourier integral transform, the method of transfer matrix is extended to the scattering of elastic waves by a plane interface crack in layered media, and the problems are reduced to a set of dual integral equations in matrix form. As an example, the far field modes of scattering of elastic waves by a plane interface crack in a layered half space have been presented. Amplitudes in far field modes are plotted versus incident wave frequency for several groups of different material combinations, and the numerical results show that resonance peaks occur at some frequencies. The frequencies at which the resonanse peaks occur for P and SV waves are almost the same.
基金supported by the National Natural Science Foundation of China(Nos.10725210,10832009 and 10432030)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20060335107)the Program for New Century Excellent Talents in University(No.NCET-05-05010).
文摘The method of reverberation-ray matrix （MRRM） is extended and modified for the analysis of free wave propagation in anisotropic layered elastic media. A general, numerically stable formulation is established within the state space framework. The compatibility of physical variables in local dual coordinates gives the phase relation, from which exponentially growing functions are excluded. The interface and boundary conditions lead to the scattering relation, which avoids matrix inversion operation. Numerical examples are given to show the high accuracy of the present MRRM.
文摘从TTI介质一阶应力—速度方程出发,利用旋转交错网格高阶有限差分方法,将非分裂完全匹配层(Non-spliting Perfect Match Layer,简称NPML)边界吸收条件和自由边界条件相结合形成组合边界条件,进行了二维三分量TTI介质弹性波场数值模拟。波场快照和炮记录表明:①采用非分裂式边界条件能较好地消除近地表大角度入射波和瞬逝波;②组合边界条件与NPML边界吸收条件相比,不仅有效地压制了边界反射,同时实现了对自由地表的模拟,获得了丰富的全波场信息,其中在地表产生的PS转换横波作为一种特殊的横波现象,可为近地表结构调查以及多波波场分析等提供有益信息;③自由地表引起的面波以及多次波对偏移结果有着重要影响,因此在实际地震资料处理中应当充分考虑自由地表条件对波场的影响效应。数值模拟结果证实了组合边界条件下二维三分量TTI介质波场数值模拟方法的可行性和正确性。
