深圳大学学报理工版

利用RFPA2D-dynamics分析软件,引入Weibull统计分布函数,描述混凝土各相材料力学性能的非均匀性,建立双丝拉拔动态数值模拟模型,研究动荷载作用下埋深变化对双丝拉拔试件力学性能的影响. 从细观单元的弹性损伤本构关系出发,研究不同埋深试件从微裂纹萌生、扩展直至贯通的动态拉拔破坏过程,得到不同埋深试件荷载-位移曲线和声发射累积数曲线,探讨埋深变化对双丝拉拔试件力学性能的影响. 结果表明,在动载作用下,双丝埋深变化对试件破坏模式影响较大,大埋深试件出现了明显的振动回弹现象; 随着埋深增加,双丝耦合效应增强,拔出过程需要消耗更多能量,试件的增强增韧效果显著.

Weibull statistical distribution function is introduced to establish dynamic numerical simulation model of twin fibers pull-out test with the software RFPA2D(realistic failure process analysis)-dynamics. The model is used to describe the non-uniformity of mechanical properties of concrete materials in different phases and study the influence of embedment depth on mechanical properties under dynamic load. According to the elastic damage constitutive relation of the meso-element, the dynamic tensile failure processes of specimens with various embedment depth are studied from micro-cracks initiation, propagation to crack penetration. The curves of load-displacement and acoustic emission cumulative number curves are also obtained. Influence of the embedment depth on properties of the twin fibers pull-out test specimens is scrutinized. The results show that variation of embedment depth of fibers has significant influence on the failure pattern of the specimen. Under dynamic loading, a phenomenon called ‘vibration springback' appears obviously in specimens with larger embedment depth. In addition, with increasing embedment depth, the twin fibers coupling effect is enhanced and the pull-out process needs more energy, which leads remarkable higher strengthen and toughness.

引言
1 理论分析
2 数值模型的建立
3 数值模拟结果分析
4 结论

图1 数值模拟模型简图<br/>Fig.1 (Color online)Sketch of numerical model

图1 数值模拟模型简图
Fig.1 (Color online)Sketch of numerical model

表1 各相材料宏观力学参数及均质度[17] 1)<br/>Table 1 Macroscopic mechanical parameters and homogeneity of materials[17]

表1 各相材料宏观力学参数及均质度[17] 1)
Table 1 Macroscopic mechanical parameters and homogeneity of materials[17]

图2 动态加载曲线<br/>Fig.2 Dynamic loading curve

图2 动态加载曲线
Fig.2 Dynamic loading curve

图3 不同埋深下的双丝拉拔试件破坏过程及应力变化<br/>Fig.3 Failure process and stress evolution of twin fibers pull-out specimens with various embedment depth

图3 不同埋深下的双丝拉拔试件破坏过程及应力变化
Fig.3 Failure process and stress evolution of twin fibers pull-out specimens with various embedment depth

图4 不同埋深试件的荷载-位移曲线<br/>Fig.4 Load-displacement curves of specimens with various embedment depth

图4 不同埋深试件的荷载-位移曲线
Fig.4 Load-displacement curves of specimens with various embedment depth

图5 不同埋深试件声发射柱状图<br/>Fig.5 Acoustic emission histogram of specimens with various embedment depth

图5 不同埋深试件声发射柱状图
Fig.5 Acoustic emission histogram of specimens with various embedment depth

表2 不同埋深试件的峰值声发射数和峰值出现时间<br/>Table 2 Peak value of acoustic emission and time-to-peak of specimens with various embedment depth

表2 不同埋深试件的峰值声发射数和峰值出现时间
Table 2 Peak value of acoustic emission and time-to-peak of specimens with various embedment depth

图6 动载和静载加载模式下的声发射累积数曲线<br/>Fig.6 Acoustic emission cumulative curves of various load pattern

图6 动载和静载加载模式下的声发射累积数曲线
Fig.6 Acoustic emission cumulative curves of various load pattern

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备注

引言

1 理论分析

2 数值模型的建立

3 数值模拟结果分析

4 结论

期刊信息

备注

引言

1 理论分析

2 数值模型的建立

3 数值模拟结果分析

4 结 论

期刊信息

4 结论