| 偏置裂纹对含双裂纹PMMA试件动态断裂影响效应研究 |
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| 作者姓名： | 杨立云 张勇进 孙金超 刘宁 程同磊 陈岐范 |
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| 作者单位： | 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： | 国家自然科学基金青年基金(51404273);国家重点研发计划(2016YFC0600903) |
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| 摘 要： | 为研究含异长双裂纹试件中次裂纹偏置对聚甲基丙烯酸甲酯(PMMA)试件动态冲击断裂行为的影响,采用数字激光动态焦散线系统和冲击加载平台进行动态焦散线试验.记录了裂纹的焦散斑图像和主裂纹的起裂时间.讨论了裂纹缺陷对主裂纹的起裂时间、裂纹扩展最大速度和裂纹尖端动态应力强度因子的影响.试验结果表明:β对主裂纹起裂时间的早晚和主裂纹扩展速度最大值产生了明显的影响,而且这种影响效应会由于主次裂纹位于PMMA试件中线的不同位置而表现出明显的差异性.主裂纹应力强度因子变化规律相似,但达到K最大值的时间表现出了差异.
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| 关 键 词： | PMMA 焦散线法 主次双裂纹 动态应力强度因子 |
| 收稿时间： | 2016-11-11 |
The effect of offset distance on dynamic fracture behavior of PMMA with double cracks |
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| Affiliation: | School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing 100083,China |
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| Abstract: | The influence of offset crack on dynamic impact fracture behavior is studied using the digital-leaser dynamic caustics system in conjunction with impact loading device.An inner mother crack along loading direction and its offset edge crack in PMMA were employed.The initiation and propagation behavior,as well as the caustics patterns of both cracks are observed.Some important dynamic fracture parameters of mother crack,such as the initiation time,maximum speed and dynamic stress intensity factor,are analyzed with different offset distance.The results show that the radio of crack spacing to crack offset distance is virtually important to the initiation time and maximum speed of mother crack,which are also influenced by the location of both cracks in the midline of the specimen.Moreover,the changes of dynamic intensity factor of mother cracks with different crack spacing are found to be similar,while the time of their maximum values are quite different. |
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