| 单侧开半圆孔PMMA试件Ⅰ型和Ⅰ-Ⅱ混合型裂纹动态扩展及数值模拟研究 |
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| 作者姓名： | 李成孝 张渊通 安晨 |
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| 作者单位： | 1中国矿业大学(北京)力学与建筑工程学院,北京 100083 |
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| 基金项目： | 国家自然科学基金;国家重点研发计划 |
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| 摘 要： | 为研究Ⅰ型和Ⅰ-Ⅱ混合型裂纹扩展问题,利用分离式霍普金森杆(SHPB)对含有预制裂纹的单侧开半圆孔(Unilateral Semicircular Hole,USH)PMMA 试件进行冲击,得到了Ⅰ型裂纹和Ⅰ-Ⅱ混合型裂纹,同时采用动态焦散线实验方法研究了裂纹扩展时程关系及裂纹扩展尖端动态应力强度因子的变化规律,利用ABAQUS 软件对试验过程进行数值模拟,研究其扩展路径。结果表明:通过试验得到的Ⅰ型和Ⅰ-Ⅱ混合型裂纹轨迹和数值模拟的结果基本相似,证明了利用数值方法模拟裂纹扩展轨迹的可行性;两种类型的裂纹在扩展过程中尖端均会出现停顿,最终都会朝着试件中轴线方向移动;使用单侧半开圆孔试件进行SHPB以及动态焦散试验可以有效研究Ⅰ型和Ⅰ-Ⅱ混合型裂纹扩展过程,为后续研究裂纹扩展提供思路。
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| 关 键 词： | 混合型裂纹扩展 动态焦散线 应力强度因子 SHPB 数值模拟 |
Study on the dynamic propagation and numerical simulation of mode Ⅰ and mixed mode Ⅰ-Ⅱ cracks in PMMA specimens with unilateral semicircular holes |
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| Affiliation: | School of Mechanics and Civil Engineering,China University of Mining & Technology-Beijing,Beijing 100083,China |
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| Abstract: | A new approach is provided to study the growth problems of mode Ⅰand modeⅠ-Ⅱmixed cracks,Split Hopkinson Pressure Bar(SHPB)is used to impact the PMMA USH(Unilateral semicircular hole)specimen containing precast crack. Results of mode Ⅰ cracks and mode Ⅰ-Ⅱmixed cracks are obtained. At the same time,dynamic caustics experiment is used to study the time history of crack growth and the change law of dynamic stress intensity factor at the crack growth tip. Numerical simulation of the test process is performed by using ABAQUS software to study its expansion path. The results show that the mode I and modeⅠ-Ⅱmixed crack trajectories obtained through experiments and the results of numerical simulation are basically similar,which proves the feasibility of using numerical methods to simulate the crack propagation. During the propagation of two types of cracks,the crack tip?will be stopped for some time,but they will eventually move towards the central axis of the test piece. Using SHPB test and dynamic caustics experiment with a Unilateral semicircular hole specimencan effectively obtain the mode Ⅰand modeⅠ-Ⅱmixed cracks,providing ideas for subsequent researches on crack propagation. |
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