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991.
横观各向同性液体饱和多孔介质中平面波的传播 总被引:11,自引:2,他引:11
基于孔隙介质的Biot理论1,研究了横观各向同性液体饱和多孔介质中平面波的传播特性。首先导出了波传播的特征方程并给出了其解析解,结果显示:有4种不同波速的平面体波传播;第一准纵波,第二准纵波,准横波和反平面横波。文中给出了波速和衰减的解析表达式,数值计算了频散曲线和衰减曲线,并讨论了各类准体波位移之间的耦合关系。 相似文献
992.
993.
Appling Mindlin's theory of thick plates and Hamilton system to propagation of elastic waves under free boundary condition, a solution of the problem was given. Dispersion equations of propagation mode of strip plates were deduced from eigenfunction expansion method. It was compared with the dispersion relation that was gained through solution of thick plate theory proposed by Mindlin. Based on the two kinds of theories, the dispersion curves show great difference in the region of short waves, and the cutoff frequencies are higher in Hamiltonian systems. However, the dispersion curves are almost the same in the region of long waves. 相似文献
994.
Atmospheric pressure waves are a notable phenomenon associated with explosive volcanic eruptions. They can provide us with information about eruption processes that are useful both scientifically and practically. In this paper, we give a brief review of studies that have been carried out on this phenomenon in the field of volcanology. Then, we introduce a prototype tool called ‘MOVE’ (Mobile Observatory for Volcanic Explosions). It is a remote-controlled vehicle carrying various instruments to observe pressure waves and the eruption processes.
PACS 91.40.Dr · 91.40.Ft · 93.65.+e · 93.85.+qThis paper was based on work presented at the 2nd International Symposium on Interdisciplinary Shock Wave Research, Sendai, Japan on March 1–3, 2005. 相似文献
995.
隐式Newmark法分析波动问题精度的探讨 总被引:2,自引:0,他引:2
本文研究了用平均加速度的Newmark积分格式求解一维平面弹性波动问题的精度。由于平均加速度的Newmark积分格式没有振幅衰减、不产生数值阻尼,因此采用此法分析波动问题会产生较强的高频振荡,尤其是加速度的计算值误差甚大。本文对防护工程中常见的平台型荷载和升压三角形荷载作用下的波动问题,应用有限元分析的实例表明:采用有数值阻尼的Newmark积分格式是改进有限元求解波动问题的一个有效方法,可以大大地提高应力和加速度求解精度。文中推荐的有数值阻尼Newmark积分格式的积分参数(=0.9,=0.49)可供工程中土与结构动力分析时参考使用。 相似文献
996.
This paper contributes to the diffraction of a solitary wave by a cylinder, governed by the Boussinesq eq. The Spectrum Method
is used to transform 2·D eqs.into a set of 1·D eqs., which is solved by F. D. M. The example given in the paper shows that
this method is both accurate and cost effective. 相似文献
997.
Two problems of heterogeneous media mechanics are investigated in the paper. The first one, concerned with the shock wave/dust layer interaction, is solved within the framework of the equilibrium model of heterogeneous media mechanics. The second problem deals with the simulation of a Riemann problem for a stratified layer of solid particles.This paper is based on work that was presented at the 20th International Colloquium on the Dynamics of Explosions and Reactive Systems, Montreal, Canada, July 31–August 5, 2005 相似文献
998.
A. M. Bragov V. L. Kotov A. K. Lomunov I. V. Sergeichev 《Journal of Applied Mechanics and Technical Physics》2004,45(4):580-585
A modified Kolsky method for dynamic tests of soft soils in an elastic holder is analyzed. It is shown the axial and radial stresses in the sample are uniform. The rational geometry of the holder is determined. Friction is found to have an effect on the dynamic strain diagram obtained. It is suggested that this effect can be reduced by lubricating the inner surface of the holder. 相似文献
999.
The process of penetration of a projectile into a semi-infinitetarget is studied in this paper. Using certain assumptions,
the propagation of plastic wave in the target is analyzed and the pressure on the surface of penetrator is given. The results
calculated from the formulas of this paper agree well with experimental data and numerical results. 相似文献
1000.
A method is proposed to study the stress concentration around a shallow spheroidal crack in an infinite elastic body. The
stress concentration is due to the diffraction of a low-frequency plane longitudinal wave by the crack. The direction of wave
propagation is established in which the combined concentration of mode I and mode II stresses is maximum
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 1, pp. 70–77, January 2006. 相似文献