基于变分渐近法预测饱和多孔介质流固耦合性能的细观力学模型

发布时间：2018-06-19 02:07

  本文选题：均匀化 + 多孔介质　； 参考：《复合材料学报》2016年04期

【摘要】：饱和岩土类多孔材料内固、液相不同属性产生的各向异性和多孔微结构的不均匀性使得材料的细观力学特性计算变得十分复杂。为准确预测岩土类材料的有效弹性性能和细观应力-应变场,基于Biot多孔弹性介质理论,建立可描述岩土类多孔材料固液相运动的能量泛函和相应的多孔弹性本构关系;利用细、宏观尺度比作为小参数将能量变分泛函渐近扩展为系列近似泛函;以场变量波动函数为未知量,通过解决近似泛函的最小化问题(驻值问题)得到波动函数的解析解,从而建立逼近物理和工程真实性的细观力学模型,并通过有限元技术得以数值实现。多孔介质材料细观力学特性算例表明:与经典均匀化理论(将液体类比为具有较高泊松比的固体材料)相比,基于变分渐近均匀化细观模型预测的多孔介质材料细观力学特性更精确,尤其是能准确重构多孔微结构内局部应力-应变场分布,为损伤破坏、局部断裂分析奠定了坚实基础。
[Abstract]:Due to the anisotropy produced by different properties of liquid phase and the inhomogeneity of porous microstructure in porous materials of saturated rock and soil, the calculation of meso-mechanical properties of porous materials becomes very complicated. In order to accurately predict the effective elastic properties and the meso-stress-strain field of geotechnical materials, based on Biot's theory of porous elastic medium, the energy functional and the corresponding porous elastic constitutive relations can be established to describe the solid-liquid movement of the porous materials of rock and soil. The energy variational functional is asymptotically extended to a series of approximate functional by using the fine and macroscopic scale ratio as a small parameter, and the analytical solution of the wave function is obtained by solving the minimization problem (the stationary value problem) of the approximate functional with the wave function of the field variable as the unknown. A meso-mechanical model approaching physical and engineering authenticity is established and realized numerically by finite element technique. An example of meso-mechanical properties of porous media shows that compared with the classical homogenization theory, the liquid is compared to a solid material with a high Poisson's ratio. The meso-mechanical properties of porous media based on variational asymptotic homogenization meso-model are more accurate, especially the local stress-strain field distribution in porous microstructures can be reconstructed accurately, which lays a solid foundation for damage failure and local fracture analysis.
【作者单位】： 重庆大学土木工程学院;重庆大学山地城镇建设与新技术教育部重点实验室;
【基金】：国家自然科学基金(11272363,51279218)
【分类号】：TB301
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本文编号：2037868