Thermo‐hydro‐mechanical modeling of unsaturated soils using isogeometric analysis: Model development and application to strain localization simulation
Thermo‐hydro‐mechanical modeling of unsaturated soils using isogeometric analysis: Model development and application to strain localization simulation
复制标题
DOI：
10.1002/nag.3015
复制
发表时间：
2019-11
影响因子：
4
通讯作者：
Shahriar Shahrokhabadi;T. D. Cao;F. Vahedifard
中科院分区：
文献类型：
--
作者：
Shahriar Shahrokhabadi;T. D. Cao;F. Vahedifard
本研究提出一个非饱和土的热-水-力学（THM）模型，使用等几何分析（伊加）。该框架采用Bézier提取将伊加连接到传统的有限元分析（FEA），将当前的研究作为开发伊加-FEA框架以解决非饱和土壤中THM问题的首批尝试之一。伊加提供了更高水平的单元间连续性，使其成为解决高度非线性问题的一种有吸引力的方法。线性动量，质量和能量平衡的控制方程耦合的平均程序的基础上的混合混合物理论。Drucker‐Prager屈服面用于限制修正后的有效应力，其中模型遵循小应变、准静态加载条件。表面张力的温度依赖性在土壤水分保持曲线中实现。非均匀有理B-样条（NURBS）基函数用于标准Galerkin方法和平衡方程的弱公式。位移、毛细管压力、气体压力和温度是四个独立的量，在空间离散化中用NURBS近似。用该框架模拟了不同温度和位移速度下不排水密实砂土在平面应变双向压缩作用下的应变局部化。结果表明，位移速率的增加导致的等效塑性应变的减少，而温度的增加导致的等效塑性应变的增加。研究结果表明，拟议的伊加为基础的框架提供了一个可行的替代方案，解决THM在非饱和土壤中的问题。
This study presents a thermo‐hydro‐mechanical (THM) model of unsaturated soils using isogeometric analysis (IGA). The framework employs Bézier extraction to connect IGA to the conventional finite element analysis (FEA), featuring the current study as one of the first attempts to develop an IGA‐FEA framework for solving THM problems in unsaturated soils. IGA offers higher levels of interelement continuity making it an attractive method for solving highly nonlinear problems. The governing equations of linear momentum, mass, and energy balance are coupled based on the averaging procedure within the hybrid mixture theory. The Drucker‐Prager yield surface is used to limit the modified effective stress where the model follows small strain, quasi‐static loading conditions. Temperature dependency of the surface tension is implemented in the soil‐water retention curve. Nonuniform rational B‐splines (NURBS) basis functions are used in the standard Galerkin method and weak formulations of the balance equations. Displacement, capillary pressure, gas pressure, and temperature are four independent quantities that are approximated by NURBS in spatial discretization. The framework is used to simulate strain localization in an undrained dense sand subjected to plane strain biaxial compression under different temperatures and displacement velocities. Results show that an increase in the displacement rate leads to reduction in the equivalent plastic strain while an increase in the temperature leads to an increase in the equivalent plastic strain. The findings suggest that the proposed IGA‐based framework offers a viable alternative for solving THM problems in unsaturated soils.