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假定混凝土是由砂浆和骨料组成的两相非均质材料,采用块体单元法模拟骨料,有限单元法模拟砂浆,基于虚功原理,建立了混凝土细观力学仿真分析的块体元-有限元耦合方法.假定混凝土骨料为刚体,砂浆为理想弹塑性材料,采用FORTRAN语言,编制了块体元-有限元耦合分析程序.运用该耦合分析程序,对耦合面刚度敏感性进行分析,得到了合适的耦合面刚度取值量级,在此基础上,采用Drucker-Prager准则,仅考虑砂浆单元的屈服,分别研究了二维和三维混凝土试件在荷载作用下的屈服、破坏过程,计算结果符合一般规律,验证了所提方法的有效性和正确性.块体元-有限元耦合分析方法兼具块体元法和有限元法的优点,前处理简单,单元数目少,计算量小,并且充分考虑了砂浆和骨料的材料力学特性差异,可以进行含有多面体骨料的三维混凝土模型的数值模拟,较精确方便地计算混凝土在荷载作用下的应力、应变,模拟混凝土的屈服、破坏过程.
Assuming that the concrete is a two-phase heterogeneous material composed of mortar and aggregate, the bulk element method is used to simulate the aggregate and the finite element method is used to simulate the mortar. Based on the virtual work principle, the block element- Finite element method is used to simulate the stiffness of the coupling surface.Using FORTRAN language, the block-element-finite element coupling analysis program is established assuming that the concrete aggregate is a rigid body and the mortar is an ideal elastic-plastic material.Using this coupling analysis program, Based on the Drucker-Prager criterion, considering only the yield of mortar elements, the yield and failure processes of two-dimensional and three-dimensional concrete specimens under load were studied respectively. The calculation results are in accordance with the general laws, which verify the validity and correctness of the proposed method.Lock-element coupled finite element method combines the advantages of bulk element method and finite element method with simple pretreatment, less number of elements, Small, and taking full account of the material mechanical properties of mortar and aggregate differences, you can carry out the numerical simulation of three-dimensional concrete model with polyhedron aggregate, more accurate and convenient calculation of coagulation Under load of stress, strain, yield simulation of concrete, destruction process.