偏置三维内裂纹单轴拉伸裂纹扩展数值模拟
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摘要
为研究偏置三维内裂纹在单轴应力下的裂纹扩展过程,利用三维裂纹计算软件Franc3d软件进行了数值模拟,得到了裂纹扩展过程及裂纹前缘的应力强度因子变化,计算结果表明:(1)单轴拉力作用下,预制裂纹尖端首先出现翼型裂纹,随后裂纹逐渐向四周扩展,裂纹先贯穿试件左右两面,而后贯穿试件的前后面形成贯穿型裂纹.(2)三维预制内裂纹倾角α=0°、30°时,预制裂纹尖端翼裂纹扩展后期两个翼裂纹呈现相互吸引的规律,而当三维预制内裂纹倾角α=45°、60°时,翼裂纹之间则不存在相互吸引靠近的趋势,预制裂纹内侧尖端的翼裂纹扩展要小于预制裂纹外侧尖端.(3)相对Ⅰ型应力强度因子随着预制裂纹尖端距离的变化(从相对距离0变化到相对距离1)呈现先增大后减小再增大再减小的规律,相对Ⅱ型应力强度因子随着预制裂纹尖端距离的变化呈现先减小后增大再减小再增大的趋势.
In order to study the process of crack propagation under uniaxial stress,the crack propagation process and the stress intensity factor of the front edge of the crack are obtained by the numerical simulation of the three-dimensional crack calculation software Franc 3 d. The results show that:(1)under uniaxial tension,the wing crack first appears at the tip of the precast crack,and then the crack propagates around the specimen. The crack first runs through both sides of the specimen and then through the front and back of the specimen.(2)in the case of three dimensional precast internal crack inclination α=0 degree and 30 degree,the two wing cracks at the tip of the precast crack tip exhibit mutual attraction during the later stage of crack growth. When the angle of internal crack is 45° and 60°,there is no tendency to attract and approach each other between wing cracks,and the propagation of wing crack at the inner tip of precast crack is smaller than that on the outer tip of precast crack.(3)the relative mode I stress intensity factor changes with the distance of prefabricated crack tip(from relative distance 0 to relative distance 1). Compared with the mode Ⅱ stress intensity factor,the stress intensity factor decreases first and then decreases and then increases with the change of the distance between the prefabricated crack tip and the crack tip.
In order to study the process of crack propagation under uniaxial stress,the crack propagation process and the stress intensity factor of the front edge of the crack are obtained by the numerical simulation of the three-dimensional crack calculation software Franc 3 d. The results show that:(1)under uniaxial tension,the wing crack first appears at the tip of the precast crack,and then the crack propagates around the specimen. The crack first runs through both sides of the specimen and then through the front and back of the specimen.(2)in the case of three dimensional precast internal crack inclination α=0 degree and 30 degree,the two wing cracks at the tip of the precast crack tip exhibit mutual attraction during the later stage of crack growth. When the angle of internal crack is 45° and 60°,there is no tendency to attract and approach each other between wing cracks,and the propagation of wing crack at the inner tip of precast crack is smaller than that on the outer tip of precast crack.(3)the relative mode I stress intensity factor changes with the distance of prefabricated crack tip(from relative distance 0 to relative distance 1). Compared with the mode Ⅱ stress intensity factor,the stress intensity factor decreases first and then decreases and then increases with the change of the distance between the prefabricated crack tip and the crack tip.
引文
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[11]李术才,杨磊,李明田,等.三维内置裂隙倾角对类岩石材料拉伸力学性能和断裂特征的影响[J].岩石力学与工程学报,2009,28(2):281~289.
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[2]应鹏,朱哲明,周磊,等.中低速冲击下Ⅰ型裂纹的动态断裂韧度研究[J].煤炭学报,2017,42(s2):338~345.
[3]秦洪远,黄丹,刘一鸣,等.基于改进型近场动力学方法的多裂纹扩展分析[J].工程力学,2017,34(12):31~38.
[4]崔臻,侯靖,吴旭敏,等.脆性岩体破裂扩展时间效应对引水隧洞长期稳定性影响研究[J].岩石力学与工程学报,2014,33(05):983~995.
[5]李响,怀震,李夕兵,等.基于裂纹扩展模型的脆性岩石破裂特征及力学性能研究[J/OL].黄金科学技术:1-18[2018-12-20].
[6]何理,钟冬望,宋琨.基于裂纹扩展的岩体爆破损伤计算方法[J].化工矿物与加工,2018(12):69~72.
[7]Horii H,Nemat-Nasser S.Elastic fields of interacting inhomogeneities[J].International Journal of Solids&Structures,1985,21(7):731~745.
[8]Tang C A,Lin P,Wong R,et al.Analysis of crack coalescence in rock-like materials containing three flaws-Part II:numerical approach[J].International Journal of Rock Mechanics&Mining Sciences,2001,38(7):925~939.
[9]黄明利,黄凯珠.三维表面裂纹相互作用扩展贯通机制试验研究[J].岩石力学与工程学报,2007,26(9):1794~1799.
[10]孙欣,朱哲明,谢凌志,等.基于SENDB试样的砂岩复合脆性断裂行为研究[J].岩石力学与工程学报,2017,36(12):2884~2894.
[11]李术才,杨磊,李明田,等.三维内置裂隙倾角对类岩石材料拉伸力学性能和断裂特征的影响[J].岩石力学与工程学报,2009,28(2):281~289.
[12]Zhu Z,Wang L,Mohanty B,et al.Stress intensity factor for a cracked specimen under compression[J].Engineering Fracture Mechanics,2006,73(4):482~489.
[13]朱珍德,林恒星,孙亚霖.透明类岩石内置三维裂纹扩展变形试验研究[J].岩土力学,2016,37(04):913~921+928.