液饱和多孔介质中三维应力波的传播

为了深入研究液饱和多孔介质中应力波的传播，提出了三维两相细观计算模型．基于此模型。应用Galerkin余量法并计及流-固耦合界面的耦合效应，利用直接耦合的技术，开发了三维流-固混合显式动力有限元计算程序．在此基础上对冲击载荷作用下液饱和多孔介质中三维应力波的传播现象进行了数值模拟，并详细讨论了孔隙率，孔隙形状等因素对应力波传播主导波形的影响．

THREE-DIMENSIONAL STRESS WAVE PROPAGATION IN FLUID-SATURATED POROUS MEDIA

A three-dimensional two-phase model for analysis of the fluid-saturated porous media, which more accords with the inner action of the media, is proposed. In this model, the solid phase and the fluid phase are separated into two really independent phases and connected on the interface. This model is in good agreement with the interaction between the solid phase and the fluid phase in the natural fluid-saturated porous media. Using Galerkin weighted residual method and considering fluid-solid coupling on the interface, the model is discretized into solid elements, fluid elements and fluid-solid coupling elements. By adopting direct-coupling technique, a three-dimensional fluid-solid mixture explicit dynamic finite element scheme is developed. Moreover, stress wave propagation in the fluid-saturated porous media is numerically simulated by using the scheme. The comparison of the wave speeds, that have been obtained by our model and the Biot's theory, as well as the wave speeds in pure solids and fluids, are made. And, the effects of the porosity and the shapes of pores on the propagation characteristic of main waves are analyzed in detail. The research results show that the velocities obtained by our model are more reasonable. The faster velocities given by Biot's theory further indicate that owing to the homogenization treatment in the generally used theories, the object investigated is a fussy substitutive model, which can not fully reflect the characteristic of stress wave propagation in the true media.