疲劳裂纹扩展前缘形貌分析及数值模拟
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摘要
为研究疲劳裂纹扩展过程中裂纹前缘形貌的变化规律,按照试验标准设计2024HDT铝合金断裂韧度试验,获取疲劳裂纹前缘形貌;通过有限元仿真研究了裂纹前缘应力强度因子的分布规律,对裂纹前缘形状进行数值模拟。结果表明:贯穿厚度平面裂纹将首先由试样缺口根部的中心层部位启裂,裂纹前缘在疲劳扩展过程中由初始直裂纹演变为椭圆形前缘裂纹。
In order to study the variation of crack tip morphology during fatigue crack propagation,the fracture toughness test of 2024 HDT aluminum alloy was designed according to the test standard,and the fatigue crack leading edge morphology was obtained. The distribution law of stress intensity factor in crack front is studied by finite element simulation,and the shape of crack leading edge is numerically simulated. The results show that the crack through the thickness plane will firstly be cracked from the central layer of the notch root of the specimen,and the crack leading edge will evolve from the initial straight crack to the elliptical leading edge crack during the fatigue expansion process.
In order to study the variation of crack tip morphology during fatigue crack propagation,the fracture toughness test of 2024 HDT aluminum alloy was designed according to the test standard,and the fatigue crack leading edge morphology was obtained. The distribution law of stress intensity factor in crack front is studied by finite element simulation,and the shape of crack leading edge is numerically simulated. The results show that the crack through the thickness plane will firstly be cracked from the central layer of the notch root of the specimen,and the crack leading edge will evolve from the initial straight crack to the elliptical leading edge crack during the fatigue expansion process.
引文
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2 Costa J D M,Ferreira J A M. Effect of stress ratio and specimen thickness on fatigue crack growth of CK45 steel[J]. Theoretical&Applied Fracture Mechanics,1998,30(1):65-73
3 Pantelakis S G,Petroyiannis P V,Bouzakis K D,et al. Surface hardness increase of 2024 aluminum alloy subjected to cyclic loading[J]. Theoretical and Applied Fracture Mechanics,2007,48(1):68-81
4 Dougherty J D,Padovan J,Srivatsan T S. Fatigue crack propagation and closure behavior of modified 1070 steel:Finite element study[J]. Engineering Fracture Mechanics,1997,56(2):189-212
5 秦剑波.整体加筋结构裂纹转折理论及其研究[D].西安:西北工业大学,2006Qin Jianbo. Theory and research on crack transition of integral reinforced structure[D]. Xi'an:Northwestern Polytechnical University,2006
6 Judt P O,Ricoeur A. Crack growth simulation of multiple cracks systems applying remote contour interaction integrals[J]. Theoretical&Applied Fracture Mechanics,2015,75:78-88
7 Sih G C,Barthelemy B M. Mixed mode fatigue crack growth predictions[J]. Engineering Fracture Mechanics,1980,13:439-451
8 Tanaka K. Fatigue crack propagation from a crack inclined to the cyclic tensile axis[J]. Engineering Fracture Mechanics,1974,6(3):493-507
9 李清,郭洋,田策,等.不同角度裂纹缺陷对材料动态断裂行为的影响[J].科学技术与工程,2016,16(28):1-5Li Qing,Guo Yang,Tian Ce,et al. Effect of material crack flaws on dynamic fracture behavior[J]. Science Technology and Engineering,2016,16(28):1-5
10 苏少普,董登科,张海英.基于Abaqus/Python的疲劳裂纹扩展分析研究[J].科学技术与工程,2015,15(27):193-198Su Shaopu,Dong Dengke,Zhang Haiying. Fatigue crack growth analysis based on abaqus/python[J]. Science Technology and Engineering,2015,15(27):193-198