深圳大学学报理工版

在考虑各相材料细观非均匀性前提下,利用动力有限元分析软件RFPA3D-dynamics建立混凝土双丝拉拔三维动态数值模型,分析不同加载速率对混凝土双丝拉拔试件破裂性能的影响. 从细观单元的弹性损伤本构关系出发,得到各试件的损伤破坏全过程图、界面剪应力分布曲线、声发射柱状图、累积声发射数曲线和声发射总能量分析. 结果表明,不同加载速率下,混凝土双丝拉拔试件的破裂过程均经历弹性阶段、弹-塑性损伤阶段、界面脱黏阶段和钢纤维拔出阶段. 随着加载速率越大,试件的裂纹扩展速率越快,界面剪应力传递也越快,累积声发射数越大,声发射总能量越大.

Under the premise of considering the mesoscopic heterogeneity of each phase material, we use the dynamic finite element analysis software RFPA3D-dynamics to establish a three-dimensional dynamic numerical model of concrete twin fibers pull-out test and study the effect of different loading rates on fracture performance of concrete twin fibers pull-out specimens. Based on the elastic damage constitutive relation of mesoscopic elements, the failure diagram of the whole process, distribution curve of interfacial shear stress, acoustic emission(AE)histogram, accumulative AE curves and AE energy analysis of each specimen have been obtained. The results show that the fracture process of concrete twin fibers pull-out specimens under different loading rates goes through the following stages: elastic stage, elastic-plastic damage stage, interface debonding stage and steel fiber pull-out stage. The higher the loading rate, the faster the crack propagation and the interfacial shear stress transmission, and the higher the cumulative acoustic emission counts and the total acoustic emission energy.

引言
1 基本原理
2 数值模型与参数
3 数值模拟结果与讨论
4 结论

图1 数值模拟模型(单位:mm)<br/>Fig.1 (Color online)Numerical simulation model(unit:mm)

图1 数值模拟模型(单位:mm)
Fig.1 (Color online)Numerical simulation model(unit:mm)

表1 数值模型力学参数1)<br/>Table 1 Mechanical parameters of numerical model

表1 数值模型力学参数1)
Table 1 Mechanical parameters of numerical model

图2 加载曲线
Fig.2 Loading curves

图3 不同加载速率下试件的应力演化过程

图4 界面剪应力分布曲线(t=300 μs)<br/>Fig.4 Interfacial shear stress distribution curves(t=300 μs)

图4 界面剪应力分布曲线(t=300 μs)
Fig.4 Interfacial shear stress distribution curves(t=300 μs)

图5 不同加载速率下试件的主应力图(t=10 μs)<br/>Fig.5 (Color online)Principle stress diagram of specimens under different loading rates(t=10 μs)

图5 不同加载速率下试件的主应力图(t=10 μs)
Fig.5 (Color online)Principle stress diagram of specimens under different loading rates(t=10 μs)

图6 不同加载速率试件的声发射柱状图<br/>Fig.6 Acoustic emission histogram of specimens with different loading rates

图6 不同加载速率试件的声发射柱状图
Fig.6 Acoustic emission histogram of specimens with different loading rates

表2 不同加载速率下单元开始破坏时间及声发射峰值<br/>Table 2 Element damage initiation time and acoustic emission peak under different loading rates

表2 不同加载速率下单元开始破坏时间及声发射峰值
Table 2 Element damage initiation time and acoustic emission peak under different loading rates

图7 不同加载速率下试件的累积声发射数曲线<br/>Fig.7 Accumulative acoustic emission curves with different loading rates

图7 不同加载速率下试件的累积声发射数曲线
Fig.7 Accumulative acoustic emission curves with different loading rates

表3 不同加载速率下试件的声发射总能量<br/>Table 3 Total acoustic emission energy with different loading rates

表3 不同加载速率下试件的声发射总能量
Table 3 Total acoustic emission energy with different loading rates

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备注

引言

1 基本原理

2 数值模型与参数

3 数值模拟结果与讨论

4 结论

期刊信息

备注

引言

1 基本原理

2 数值模型与参数

3 数值模拟结果与讨论

4 结 论

期刊信息

4 结论