作者：赵兴华, 蔡力勋, 包陈

作者单位：西南交通大学力学与工程学院 应用力学与结构安全四川省重点实验室, 四川 成都 610031

关键词：含径向对称裂纹圆环;疲劳裂纹扩展;柔度法;应力强度因子;有限元分析;材料试验

摘要：

针对传统断裂测试试样受构型的限制往往尺寸较大,无法满足小尺寸金属管疲劳断裂行为测试要求的问题,设计新构型小尺寸试样。并基于有限元分析和柔度理论,建立含径向双边对称裂纹圆环(O-ring with double radial symmetric cracks,DOR)小试样的裂纹长度预测公式和应力强度因子公式,进而提出DOR小试样的疲劳裂纹扩展试验新方法。应用5083-H112铝合金加工成含径向裂纹小管试样和标准CT试样,开展疲劳裂纹扩展速率对比试验。结果显示,基于DOR试样得到的5083-H112铝合金的疲劳裂纹扩展规律与CT试样的试验结果相吻合,证明新方法的有效性。经过对试样端口的测量和分析,试样两侧对称裂纹的扩展量基本一致,说明对称裂纹满足唯一性要求,且不同于CT试样,该圆环试样裂纹前缘非常平直,表明圆环构型试样沿厚度方向的约束状态更加接近。

Test method of fatigue crack propagation of small size O-ring with double radial symmetric cracks

ZHAO Xinghua, CAI Lixun, BAO Chen

Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China

Abstract: Fatigue crack propagation behavior of small scale size tube founded in nuclear fuel cladding, aerospace equipment, and other fields widely, has great value for research. However, the traditional test specimen is bigger restricted by configuration, often can't require the requirements. To solve the problem which is mentioned above, a small scale size sample with a new configuration has been designed. Based on the finite element analysis and the compliance technique, a compliance formula and a stress intensity factor expression for the small scale size specimen O-ring configuration with double radial cracks (DOR) are proposed in the present study. A novel test method for fatigue crack propagation behavior of small scale size DOR according to the compliance technique has been developed. The aluminum alloy 5083-H112 was adopted to complete the fatigue crack propagation rate tests by using both the small scale size DOR and the standard CT. Results show that fatigue crack propagation rates for the small scale size DOR and the standard CT are close to each other and the validity of the method proposed was proved. The symmetrical cracks propagation quantity are almost the same on both sides of the sample through measurement and analysis of the fracture, it is show that symmetric cracks satisfies the requirement of uniqueness. And, different from CT specimen, the crack front of small scale size DOR is very straight, indicate that the small scale size DOR constraint condition is much closer along the thickness direction.

Keywords: O-ring with double radial symmetric cracks(DOR);fatigue crack propagation;compliance method;stress intensity factor;finite element analysis;material test

2015, 41(7): 1-5  收稿日期: ;收到修改稿日期: 

基金项目: 

作者简介: 

参考文献

[1] 黄学伟,蔡力勋,包陈,等. 基于低周疲劳损伤的裂纹扩展行为数值模拟新方法[J]. 工程力学,2011,28(10):202-208.
[2] 方钦志,张石山,赵明嗥,等. 疲劳裂纹扩展柔度法测量系统研究[J]. 实验力学,2000,15(1):110-114.
[3] Ding F, Feng M L, Jiang Y Y. Modeling of fatigue crack growth from a notch[J]. International Journal of Plasticity,2007,23(7):1167-1188.
[4] 龚明,赵建华,董本涵,等. 含孔薄板孔边疲劳裂纹的萌生和扩展[J]. 航空学报,2002,23(3):202-205.
[5] 郭加林,尹志民,王华,等. 微量Sc和Zr对2524SZ合金薄板疲劳裂纹扩展特性的影响[J]. 中国有色金属学报,2010,20(5):8278-8278.
[6] Jones A T. A radially cracked, cylindrical fracture toughness specimen engineering fracture mechanics[J]. Pergamon Press,1974(6):435-466.
[7] Ahmad J, Ashbaugh N E. Constant KI crack-propagation test specimens[J]. International Journal of Fracture,1982,19(2):115-129.
[8] Clark G. Fatigue crack growth through residual stress fields-theoretical and experimental studies on thick-walled cylinders[J]. Theoretical and Applied Fracture Mechanics,1984,2(2):111-125.
[9] 马德林. 集中力加载下含径向裂纹圆环试样的K1解[J].兵器材料学与工程,1987(12):6-11.
[10] Shi H J, Niu L S, Mesmacque G, et al. Branched crack growth behavior of mixed-mode fatigue for an austenitic 304L steel[J]. International Journal of Fatigue,2000,22(6):457-465.
[11] GB/T 6398—2000金属材料疲劳裂纹扩展速率试验方法[S]. 北京:中国标准出版社,2000.