| 条形药包爆炸全场应变以及裂纹动态断裂特性研究 |
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| 作者姓名： | 左进京 杨仁树 汪文良 龚敏 赵勇 |
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| 作者单位： | 1.北京科技大学土木与资源工程学院，北京 100083 |
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| 基金项目： | 中国博士后科学基金资助项目（2020TQ0032）；国家自然科学基金资助项目（51934001）；中央高校基本科研业务费专项资金资助项目（FRF-TP-20-037A1, FRF-IDRY-20-019） |
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| 摘 要： | 为了探究不同起爆位置下条形药包全场应变以及裂纹动态断裂特性，采用爆炸荷载动态焦散线实验系统和数字图像相关方法（DIC），开展了爆破模型实验研究。研究结果表明:条形药包一端起爆时，起爆点处翼裂纹扩展长度最小，随着炸药爆轰的传播，翼裂纹扩展长度增长；中心起爆时，中心位置翼裂纹扩展长度小于两端位置翼裂纹扩展长度，一端起爆时非起爆端翼裂纹扩展长度最长。无论中心起爆或一端起爆，条形药包中心区域翼裂纹扩展主要为Ⅰ型裂纹，并且中心翼裂纹起裂韧度最大，端部翼裂纹为以Ⅱ型为主的Ⅰ?Ⅱ型复合裂纹。一端起爆时，拉压应变作用范围沿炸药传爆方向传递，且非起爆端拉压应变作用区域大于起爆端，压应变最大值为距起爆点约0.67 ~ 0.83倍的装药长度。中心起爆时，拉压应变的作用过程沿起爆中心向两端呈对称形式传播，中心点位置应变最大。两种起爆方式下都出现端部压应力集中现象。
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| 关 键 词： | 条形药包 数字图像相关 动态焦散线 爆炸全场应变 应力强度因子 |
| 收稿时间： | 2021-10-19 |
Explosive full-field strain and crack dynamic fracture characteristics of a linear shaped charge |
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| Affiliation: | 1.School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China2.Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education), University of Science and Technology Beijing, Beijing 100083, China3.State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China |
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| Abstract: | This study explores the full-field strain and dynamic fracture characteristics of a linear shaped charge under different initiation positions. The explosion dynamic caustic line experiment system is employed to examine the characteristics of the blast crack propagation of the linear shaped charge at different initiation positions and capture the dynamic information of the crack tip propagation speed and stress intensity factor. Furthermore, the digital image correlation method was used to show the strain evolution law of the linear shaped charge at different initiation positions, as well as the medium strain response of the charge near the explosion zone caused due to detonation transmission. The results show that in end-initiation, the wing crack length at the initiation point is the smallest, and the wing crack propagation length increases with the detonation propagation of the explosive. Conversely, in center-initiation, the propagation length of the wing cracks at the center is less than those at both ends. The propagation length of the wing cracks in the noninitiation end is the longest for end-initiation, where the velocities of the wing crack initiation and propagation are minimum. For center-initiation, the wing crack initiation and propagation velocities are the smallest, i.e., irrespective of the initiation position, the wing crack initiation and propagation velocities at the initiation point are lower than that at other locations. Based on the dynamic stress intensity factor analysis, irrespective of the initiation position, the center wing cracks are type Ⅰ cracks with the largest crack toughness, the stress intensity factor value is the maximum, and the wing cracks at the ends are type Ⅰ?Ⅱ composite cracks dominated by type Ⅱ. Based on the full-field strain analysis of the linear shaped charge, at end-initiation, the range of tension and strain action is mainly along the direction of explosive transmission, and the tension and strain action area at the noninitiation end is larger than that at the initiation end. The corresponding position of the maximum compressive strain is 0.67–0.83 times the charge length from the initiation point. When the center detonates, the action process of tension and compression strain propagates symmetrically from the center to both ends of the initiation, and the strain at the center is the largest. The compressive stress concentration at the end occurs under both initiation modes because the explosive transmission is the process of energy accumulation; thus, the effect of the explosive explosion on the medium grows increasingly stronger along the direction of explosive transmission. |
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