为了研究动荷载作用下裂纹角度对相互贯通裂纹动态断裂特性的影响，采用动焦散试验系统进行了含预制裂纹的三点弯冲击试验。试验结果表明：两分支裂纹相互贯通，在动荷载作用下翼裂纹只会从与竖直方向夹角较小的分支裂纹尖端起裂扩展，当有一支分支裂纹起裂后，另一分支裂纹动态应力强度因子快速下降，试件内应变能重新分布；起裂的翼裂纹首先沿准竖直方向扩展，当扩展到试件约2/3高度后，翼裂纹扩展速度下降，扩展轨迹弯曲程度加大，I-II复合型断裂明显；分支裂纹起裂瞬间的 和 随着该裂纹与竖直方向夹角的增加而增大，其扩展的平均速度随着夹角的增加而减小。
Abstract
In order to study the effect of crack angle on dynamic fracture properties of interconnected cracks under dynamic load, the fracture experiments of three-point bending beam containing pre-cracks were carried out by dynamic caustics test system. Experimental results show that in two interconnected cracks, the wing crack only initiates from the smaller angle branch crack tip under dynamic loading. After one branch crack initiates, another tip stress intensity factor quickly drops down and strain energy redistributes in the specimen. The wing crack of initiation firstly expands along the quasi-vertical direction. The wing crack propagation speed decreases, the path bending degree increases and I - II complex fracture phenomenon is obvious after the wing crack extends to about 2/3 height of the specimen. With the increase of angle between the branch crack and vertical direction, and of branch crack at initiation moment increase but the average speed of the wing crack propagation decreases.
关键词
动荷载 /
动焦散 /
相互贯通裂纹 /
动态应力强度因子
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Key words
dynamic load /
dynamic caustic /
interconnected crack /
dynamic stress intensity
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参考文献
[1]. 任利，谢和平，谢凌志，等. 基于断裂力学的裂隙岩体强度分析初探[J]. 工程力学，2012, 30(2): 156-162, 168.
Ren Li, Xie Heping, Xie Lingzhi, et al. Preliminary study on strength of cracked rock specimen based on fracture mechanics [J]. Engineering Mechanics, 2012, 30(2): 156-162,
168.
[2]. Lee P Y, Sun Z C, Liao M, et al. The study of crack mechanism during arc brazing of cooling pipe to ITER magnet support system [J]. IEEE Transactions on Applied Superconductivity, 2014, 24(3): 1-14.
[3]. Kalthoff J F. Shadow optical method of caustics [R]. Handbook on Experimental Mechanics, Second Revised Edition (USA) VCH Publishers Inc. 1993: 407-476.
[4]. Yuichi Kawagishi, Masayuki Shozu, Yukio Hirose. Experimental evaluation of stress field around crack tip by caustic method [J]. Mechanics of Materials, 2001, 33(12): 741-757.
[5]. 杨仁树，王雁冰，候丽冬，等. 冲击荷载下缺陷介质裂纹扩展的DLDC试验[J]. 岩石力学与工程学报，2014, 33(10): 1971-1976.
Yang Renshu, Wang Yanbing, Hou Lidong, et al. DLDC experiment on crack propagation in defective medium under impact loading [J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(10): 1971-1976.
[6]. Kalthoff J F. On the measurement of dynamic fracture toughness-a review of recent work [J]. International of Fracture, 1985, 27(3): 277-298.
[7]. Theocaris P S, Andrianopoulous N P. Dynamic three-point-bending of short beams studied by caustic [J]. International Journal of Solids & Structures, 1977, 17(7): 707-715.
[8]. 姚学锋，方竞. 冲击荷载下扩展裂纹尖端动态能量释放率分布的焦散线分析[J]. 爆炸与冲击，1996, 16(2): 111-116.
YAO Xuefeng, FANG Jing. Analysis of caustics on dynamic energy release rate of running crack tip under impact load [J]. Explosion and Shock Waves, 1996, 16(2): 111-116.
[9]. 贾敬辉，张永彬. 动荷载作用下三点弯曲梁的破坏形式与偏置裂纹位置的关系[J]. 武汉理工大学学报，2012, 34(11): 84-87.
Jia Jinghui, Zhang Yongbing. Relations Between the Location of the Notch and the Failure Mode in Three-point Bending Beam under the Dynamic Loads [J]. Journal of Wuhan University of Technology. 2012, 34(11): 84-87.
[10]. 宋义敏，何爱军，王泽军，等. 冲击荷载作用下岩石动态断裂试验研究[J]. 岩土力学，2015, 36(4): 965-970.
Song Yimin, He Aijun, Wang Zhejun, et al. Experiment study of the dynamic fractures of rock under impact loading [J]. Rock and Soil Mechanics, 2015, 36(4): 965-970.
[11]. Fender M L, Lechenault F, Daniels K E. Universal Shapes Formed by Two Interacting Cracks [J], Physical Review Letters. 2010, 105(12): 1－4.
[12]. ROSSMANITH H P, DAEHNKE A, KNASMILLNER R E K, et al. Fracture mechanics applications to drilling and blasting [J]. Fatigue and Fracture Engineering Materials and Structures, 1997, 20(11): 1617–1636.
[13]. Manogg P. Anwendung der schattenoptik zur untersuchungdes zerreissvorgangs von platen [D]. West Germany: University of Freiburg, 1964.
[14]. 李清，郭洋，马万权，等. 半圆盘构件冲击断裂特性的动态焦散线实验研究[J]. 振动与冲击，2016, 35(9): 52-58.
Li Qing, Guo Yang, Ma Wanquan,et al. Dynamic caustics tests for semi-circular specimen under impact loading [J]. Journal of Vibration and Shock, 2016, 35(9): 52-58.
[15]. Theocaris P S, Gdoutos E E. The modified Dugdale-Barenblatt model adapted to various fracture configurations in metals［J］. Int. J. Fracture, 1974, 10(4): 549－564．
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