基于改进随机骨料模型的混凝土细观断裂模拟

Simulation of meso-fracture for concrete based on the developed random aggregate model

为了更好地研究混凝土的力学性能和破坏机理,该文在已有细观力学模型的基础上,发展了高效的骨料投放方法及单元筛分准则。基于连续介质力学的方法,采用弹性损伤本构关系描述混凝土细观各相材料力学行为,建立了随机骨料数值模型及相应的细观单元参数选取方法。以多组不同骨料分布的Petersson三点弯曲梁为例,分析和探讨了混凝土的破坏机理。结果表明,该数值模型能较好地模拟混凝土I型断裂拉伸破坏全过程,与试验结果表现出良好的一致性。

Based on former meso-mechanics models, an efficient aggregates deposition method and an elements division criterion are developed in order to study the mechanical characteristic and the failure mechanism of concrete better. Based on the continuum mechanics, a reasonable meso-mechanics model of concrete and a parameters chosen method for meso-elements are presented which use the elastic damaged stress-strain relations to describe mechanical behaviors of the concrete. Numerical experiments with random distribution of aggregates for concrete samples for simulating Petersson＇s 3-point bending beam are then accomplished, from which the failure mechanism of concrete on meso scale is investigated. It is shown that the numerical mode is able to capture the complete process of concrete mode-I tensile fracture,which shows good agreement with corresponding experimental results.