摘要
常规的弹塑性模型难以模拟材料破坏时由于内部损伤累积引起的变形局部化带形成过程。将岩土材料抽象为含有孔洞的球形体胞单元的集合体,采用一个标量——孔洞体积百分比来刻划单元的损伤程度,基于细观损伤力学提出了一个适用于岩土材料的塑性损伤模型。将该模型通过用户子程序嵌入到大型有限元商业软件MRAC中,研究岩土材料的局部化剪切带形成过程。采用该模型,成功地对平面应力条件下岩土材料单轴受压和单轴受拉试件的局部化破坏分别进行了数值模拟。采用该模型,对拱坝在超水载作用下的变形局部化进行了研究,数值计算结果表明,上游坝踵处最先发生变形局部化现象。
Elastoplastic models can＇t simulate strain localization due to ductile damage evolution. A porous geomaterial is modeled as an aggregate of spherical thick-walled shells, so the damage of a representative volume element can be characterized by a scalar variable, i.e. the void volume fraction, and a coupled plastic damage model for geomaterials based on rnicromechanics was proposed. This model was implemented into the commercial FEM software MARC through a user subroutine, and strain localization of geomaterials was studied. Shear band formation due to void nucleation and growth were successfully simulated in a specimen of geomaterial under plane stress compression and tension by the model respectively. Shear band formation in an arch dam under overloading was studied also. It is shown that the strain localization appeared first at the heel of the arch dam.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2007年第5期865-870,共6页
Rock and Soil Mechanics
基金
国家自然科学基金重大项目(No.50490270)
国家973课题(No.2002cb412708)资助项目
关键词
岩土材料
孔洞体积百分比
塑性损伤模型
拱坝
变形局部化
geomaterials
void volume fraction
damage coupled plastic model
arch dam
strain localization
