| 白国娟,张晓晶*,徐武,汪海.裂纹尖端张开角准则的稳态裂纹扩展实验研究[J].实验力学,2012,27(4):454~462 |
| 裂纹尖端张开角准则的稳态裂纹扩展实验研究 |
| Experimental Analysis of Stable Crack Extension based on Crack Tip Opening Angle Criterion |
| 投稿时间：2011-12-30 修订日期：2012-04-27 |
| DOI： |
| 中文关键词: 薄壁结构 裂纹尖端张开角 裂纹稳态扩展 剩余强度 阻力曲线KR |
| 英文关键词:Thin wall structures Crack tip opening angle Stable crack growth Residual strength KR-curve |
| 基金项目: |
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| 中文摘要: |
| ASTM和ISO已发布获得低约束条件下断裂性能和裂纹稳态扩展阻力曲线的标准,标准中采用多种试验方法确定临界裂纹张开角度来表征板材的裂纹稳态扩展。采用准静态裂纹扩展试验方法,通过摄像技术测定裂纹尖端张开角(CTOA),验证标准对1mm厚度2024-T3铝合金板稳态裂纹扩展行为的有效性。研究了试样构型、裂纹尺寸和是否疲劳预制裂纹对裂纹稳态扩展过程中CTOA的影响。试验结果表明：裂纹扩展2mm后,距离裂纹尖端1mm处的CTOA趋于一个恒定值6°,这个值与试样构型和裂纹长度无关;同时,不预制疲劳裂纹对CTOA值和试样的最大剩余强度影响较小。 |
| 英文摘要: |
| ASTM and ISO had published their fracture mechanics test standards on specimens with low constraint. Various methods had been used to determine the crack tip opening angle during stable crack extension to characterize the material fracture resistance. In this paper the ASTM standard is validated by studying the crack stable growth behavior of aluminum alloy sheet with 1mm thickness. The crack tip opening angle is measured by using optical microscopy method. Experimental results have shown that the crack tip opening angle is nearly a constant value of 6 degree after about 2mm of stable tearing. This value is independent on specimen geometry and initial crack length. It is also found that the constant crack tip opening angle and residual strength obtained from saw and fatigue cracked specimens are nearly the same. |
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