层合界面单元在混凝土细观数值模拟中的应用

Application of interface laminar element in meso-level numerical simulation of concrete

为了解决混凝土细观数值模拟中单元数量过多、计算效率不高的问题,提出了层合界面单元的概念。在交叠骨料微步长迭代自动调整算法的基础上,采用任意凹凸型骨料随机配置模型,生成了混凝土细观数值试件。通过对主要影响因素进行组合分析,建立了层合界面单元模型。同时,分析了界面单元中不同材料组分比例及界面厚度对该单元力学性质的影响,进而研究了界面单元对混凝土试件宏观表征强度的影响,并用数值算例验证了模型的有效性。数值算例表明,所建立的层合界面模型较为合理地模拟了混凝土界面过渡区对试件力学性能的影响,揭示了界面强度变化对混凝土试件强度的影响规律。

The. number of the elements in the meso - level numerical simulation of concrete is too many and the calculation effi- ciency is low, so the concept of the interface laminar element is proposed. Based on the auto - fine adjustment algorithm of micro - step iteration of overlapping aggregate, a meso - level concrete numerical model is generated by the random aggregate model collocated by the random concave - convex aggregate. By analyzing the combination of the main influential factors, the interface laminar element is established. Meanwhile, the influence of the proportions of different components as well as the width of inter- face laminar on the mechanical features of the interface laminar element is analyzed ; and furthermore, the impacts of the interface laminar element on the macro - level strength of concrete specimen are studied. A numerical example is given to verify the ration- ality of the model. The results show that the proposed element can simulate the effects of interface laminar region on the mechani- cal behavior of concrete specimen and reveal the influential laws of strength variation of the interface laminar region on the con- crete specimen.