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混凝土三点弯曲梁动态断裂破坏的扩展有限元分析
作者：王瑾，米力，杨红楼
（鄂尔多斯职业学院，内蒙古 鄂尔多斯 017000）
摘要：基于扩展有限元理论，模拟混凝土三点弯曲梁在不同加载速率下的断裂破坏过程，研究加载速率对混凝土三点弯曲梁断裂损伤特性的影响。结果表明，不同加载速率下混凝土梁的荷载-挠度曲线以及荷载-开口位移曲线均包含线性上升、非线性上升与非线性下降3个阶段，混凝土梁发生失稳断裂破坏所需的能量会随着加载速率的增大而增大。混凝土三点弯曲梁的应力强度因子增幅会随加载速率的增大而增大。不同加载速率下混凝土三点弯曲梁构件的损伤耗能发展全过程均可被划分为损伤初始阶段、损伤萌发与稳定发展阶段以及损伤不稳定阶段。
关键词：扩展有限元；加载速率；断裂韧度；应力强度因子；损伤耗能
中图分类号：TU375.1 文献标识码：A 文章编号：1001-702X（2020）02-0068-04
Extended finite element analysis of dynamic fracture failure of concrete three-point bending beams
WANG Jin，MI Li，YANG Honglou
（Ordos Vocational College Inner Mongolia，Erdos 017000，China）
Abstract：The fracture failure process of concrete three-point bending beam under different loading rates is simulated based on the extended finite element theory. The effects of loading rate on fracture damage characteristics of concrete three-point curved beams were studied. The results show that the load-deflection curve and load-opening displacement curve of concrete beam under different loading rates all contain three stages of linear rise，nonlinear rise and nonlinear fall. The energy required for the buckling failure of the concrete beam will increase with the increase of loading rate. The amplification of stress intensity factor will increase with the increase of loading rate. The damage energy consumption of the concrete three-point bending beams under different loading rates could be divided into the initial stage of damage，the stage of damage germination，the stage of stable development and the stage of damage instability.
Key words：extended finite element，loading rate，fracture toughness，stress intensity factor，damage energy consumption