摘要
Dynamic crack propagation in brittle materials plays an important role in unJerstanding the fracture mechanism.Numerical simulations on crack propagation in the polymethyle methacrylate(PMMA)under explosive loads were carried out through Autodyn 3D code.Although the Johnson-Holmquist(JH-2)constitutive model has been widely treated as an acceptable scheme,it cannot improve the description in the post-failure response of material and reduce the mesh dependency,so the crack softening failure model are introduced in our present work based on two failure criterions.First,material parameters of JH-2 model,failure criterion,and crack softening failure model are determined from available data and calculations.The circular and rectangle thin plates are modeled to explore the fracture mechanisms for single-borehole and dual-borehole explosions.The simulation results well reproduced the entire dynamic evolutionary process of the crushed and fractured zones,crack initiation,propagation and arrest as well as secondary propagation,which successfully proved the relibilities of the combination of JH-2 constitutive model,failure criterion,and crack softening failure model and corresponding material parameters.For dual-borehole explosion,the crack linkage is well performed when borehole distance L is 20 and 30 cm;cracks are failed to link with each other at L=40 cm although main cracks have arrived into the opposite fractured zone.More importantly,it is found that the crack linkage mainly depends on L,which has an important effect on linkage style and its location.Despite a larger L makes more difficult in crack linkage,this difficulty lies not in the shortage of crack length,but in losing control of directional fracture of cracks between two boreholes.
脆性材料中动态裂纹扩展在理解断裂机制方面起着重要作用.通过Autodyn3D软件对有机玻璃(PMMA)在爆炸载荷下裂纹扩展进行了数值模拟.尽管Johnson-Holmquist(JH-2)模型被广泛认为是--种可接受的方案,但它不能改善对材料破坏后响应的描述,也不能减少对网格的依赖性,因此本文基于两个破坏准则,引入了拉伸断裂软化失效模型、首先,根据现有数据和计算,确定了JH-2模型、失效准则和裂纹软化失效模型的材料参数.通过对圆形和矩形薄板进行建模,以探讨单孔和双孔爆炸下的断裂机制.模拟结果很好地再现了破碎区和断裂区的整个动态演化过程,裂纹的起裂、扩展和止裂以及二次扩展,成功地证明了JH-2构成模型、失效准则和拉伸软化失效模型的组合及相应材料参数的可靠性.对于双孔爆炸,当孔距L=20和30cm时,裂纹贯穿良好;在L=40 cm时,虽然主裂缝已经延伸至对侧的断裂区,但裂缝未能相互贯穿.更重要的是,发现裂缝的贯穿主要取决于L,其对贯穿方式和贯穿位置有重要影响、尽管较大的L使裂缝贯穿更加困难,但该困难不在于裂缝长度不足,而在于失去了对双孔间裂纹定向扩展的控制.
作者
Chuanjin Pu
Xin Yang
Han Zhao
Zhenlin Chen
Dingjun Xiao
Changlin Zhou
Bing Xue
蒲传金;杨鑫;赵晗;陈臻林;肖定军;周昌林;薛冰(School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,China;Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province,Mianyang 621010,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Deep Underground Science and Engineering(Ministry of Education),College of Architecture and Environment,Sichuan University,Chengdu 610065,China;Chengdu Surveying Geotechnical Research Institute Co.,Ltd.of MCC,Chengdu 610023,China)
基金
the Key Research Foundation of Education Bureau of Sichuan Province(Grant No.17zd1122)
the Natural Science Foundation of Southwest University of Science and Technology(Grant No.19zx7168)
the Shock and Vibration of Engineering Materials and Struc-tures Key Laboratory of Sichuan Province(Grant No.I9kfgk07)
the Sci-ence and Technology Department of Sichuan Province(Grant No.2021 YJ0525)
National Natural Science Foundation of China(Grant No.11802255).
