| 摘要: |
| 实际构件中大量存在着半穿透型的焊接表面裂纹,对于这种力学性能不均匀三维裂纹体的弹塑性断裂力学参量(例如J积分)的探讨还比较缺乏。利用J积分直接测试方法以及适当的理论弹性修正,对存在于不同组配比的高组配焊接接头焊缝区的三维表面裂纹的J积分进行了试验研究,着重讨论了接头组配比对焊接接头试样加载过程中裂纹扩展驱动力(J积分,裂纹嘴张开位移CMOD)、应变沿积分路径分布的影响。结果表明,焊接接头试样上应变的分布趋势取决于裂纹位置和组配比的综合影响;随载荷的增加,邻近焊缝的母材区将产生应变集中;并且,随组配比的降低,该区域的应变集中程度随之提高,而焊缝区的变形量随之降低,裂纹扩展驱动力增大。 |
| 关键词: 焊接接头 表面裂纹 J积分 |
| DOI： |
| 分类号: |
| 基金项目:国家教委博士点基金(9569816) |
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| J-integral of Surface Crack in Overmatched Joint |
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LI Ji-hong, ZHANG Jian-xun, PEI Yi
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The Institute of Welding, Xi'an Jiaotong University, Xi'an, China
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| Abstract: |
| The part-through surface cracks exist widely in practical welded structure, and the investigation of the elastic plastic fracture mechanics parameters (eg. J-integral) of this three-dimensional mechanical heterogeneity is not enough. In this paper, the J-integral of surface cracks in overmatched weldment with different matching ratios has been investigated by using direct evaluation method. The influences of matching ratio of joints on the crack driving force (J-integral, crack mouth opening displacement CMOD) and strain distributions along the contour have been discussed in detail. The results indicate that the comprehensive effect of crack position and the matching ratio of welded joint dominate the distribution of strain. With the increasing of load, the obvious strain concentration may be produced in the parent metal zone close to weld. Moreover, with the decreasing of the matching ratio, the degree of the strain concentration grows, the deformation of weld metal decreases to a certain extent, and the crack driving force increases. |
| Key words: welded joint surface crack J-integral |
