混凝土三点弯曲梁裂缝断裂全过程数值模拟研究

考虑裂缝黏聚力的作用,基于Paris位移公式推导出混凝土三点弯曲梁裂缝扩展过程中断裂过程区上的裂缝张开位移的解析表达式.采用起裂韧度作为裂缝起裂及扩展的判断标准,提出了荷载作用下混凝土裂缝起裂、扩展及失稳破坏全过程的数值模拟方法,并分别与国内外断裂试验实测值及有限元计算值进行了比较.结果表明,本文提出的数值模拟方法形式简单且精度较好.

Research on numerical simulation on the whole cracking processes of three-point bending notch concrete beams

Based on Paris' displacement formula and by considering the role of cohesive stress in the fracture of concrete,a theoretical expression for crack opening displacement of three-point bending notched beams is derived.Then,with the initial fracture toughness taken as the criterion of crack initiation,the derived expression is applied in simulating the whole cracking processes of concrete,including the beginning and development of cracking as well as the subsequent failure of concrete.To test the validity and performance of the model proposed in this paper,its calculating result is compared with experimental data and that of the finite element model and a high agreement exits among them,which indicates that the proposed method is not only simple in form and application but also with high precision.