基于细观尺度的纤维混凝土力学性能研究

项目名称： 基于细观尺度的纤维混凝土力学性能研究

项目编号： No.51508146

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑环境与结构工程学科

项目作者： 洪丽

作者单位： 合肥工业大学

项目金额： 20万元

中文摘要： 以纤维混凝土为研究对象，考虑纤维混凝土由纤维、粗骨料、水泥砂浆、纤维与水泥砂浆间界面、粗骨料与水泥砂浆间界面五相细观介质组成，并基于离散单元法及多刚体-弹簧单元法，建立二维及三维纤维混凝土细观力学模型。模型中，相邻单元之间通过弹簧相连，通过界面连接弹簧的力学性能来考虑界面层的作用，然后根据连接弹簧的破坏表征纤维混凝土开裂后由连续体向非连续体的转变。其次，通过试验获得各相细观材料的力学参数，带入细观力学模型后，对纤维混凝土试验试件的破坏过程进行数值仿真，并将数值结果与试验结果进行对比分析以验证力学模型的适用性及正确性。最后，利用该细观力学模型研究纤维的力学性能、体积率、分布及方向，粗骨料粒径、数量、形状及分布，界面强度等因素对纤维混凝土宏观力学性能及破坏形态的影响。为纤维混凝土材料破坏的多尺度分析提供了依据。

中文关键词： 纤维混凝土；细观力学模型；离散单元法；界面粘结强度；破坏过程

英文摘要： Based on the discrete element method (DEM) and rigid body spring model, a two or three dimensional mesoscopic mechanical model of fiber reinforenced concrete was developed, which considered fiber reinforenced concrete as a five-phase composite material with fiber, coarse aggregates, mortar, the interface between fiber and mortar, and the interface between coarse aggregate and mortar. The crack in fiber reinforenced concrete at macro-level was represented by the failure of springs between elements. After the mechanical performances of the fiber, mortar, and interface were obtained from the experiments, the failure process of fiber reinforenced concrete was simulated by the mesoscopic mechanical model, and the simulation results were compared with that obtained from the experiments to verify the reasonable of the mechanical model. Finally, the influences of the mechanical properties, volume fraction and distribution of fiber, size, number, shape and distribution of coarse aggregate, and the interfacial strength on the mechanical performance and failure process of fiber reinforenced concrete were analyzed. This research provides theoretical references for analyzing the failure process of fiber reinforenced concrete at multi-scale.

英文关键词： fiber reinforenced concrete;mesoscopic mechanical model;discrete element method;bond strength of interface;failure process