| 王芳丽,佘崇民,郭万林.航空结构铝合金I/II复合型断裂的三维弹塑性数值分析[J].计算力学学报,2011,28(2):255~259 |
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| 航空结构铝合金I/II复合型断裂的三维弹塑性数值分析 |
| Numerical analysis of three-dimensional I/II mixed-mode elastic-plastic fracture of aeronautical structural aluminum alloy |
| 投稿时间：2009-03-13 修订日期：2009-12-17 |
| DOI：10.7511/jslx201102018 |
| 中文关键词: 三维I/II复合型弹塑性断裂 起裂角 最大周向应力准则 三维离面约束因子 |
| 英文关键词:three-dimensional I/II mixed-mode elastic-plastic fracture crack initial angle the maximum tangential stress criterion three-dimensional out-of-plane constraint factor |
| 基金项目:航空科学基金(2007ZA52011,2008ZF52062);国家自然科学基金(50805079);南京航空航天大学启动基金(S0872-GXY)资助项目. |
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| 中文摘要: |
| 在LC4CS铝合金三维I/II复合型断裂实验的基础上,对I/II复合型加载模型进行了细致的三维弹塑性有限元计算,系统分析了不同复合度Φ和厚度B对裂纹端部应力场和起裂角的影响。结果表明,对于不同Φ和B的试样,周向应力极大值和三维离面约束因子极小值出现在相同的角度;根据最大周向应力准则,在I型载荷占主导(βeq>65.45°)时,三维有限元计算的裂纹起裂角比采用二维MTS准则预测的起裂角更加接近实验结果。实验中8 mm厚度下的复合型断裂具有比采用现有二维断裂准则的预测值更小的起裂角,说明需要发展更加接近实际情况的新的三维复合型断裂准则。 |
| 英文摘要: |
| Based on three-dimensional I/II mixed-mode fracture experiments of the LC4CS aluminum alloy, three-dimensional I/II mixed-mode elastic-plastic finite element models were established. The coupled effects of mixed loading and thickness on the elastic-plastic field near the crack front and the initial angle of crack were analyzed systematically. It is shown that the angle of the maximum tangential stress is the same with the angle of the minimum three-dimensional out-of-plane constraint factor under various mixed loadings and thicknesses. Next, when the mode I loading is dominant(βeq>65.45°), the crack initiation angle of finite element calculation based on the maximum tangential stress criterion is closer to the experimental data than the value predicted by two-dimensional the maximum tangential stress criterion. Finally, The experimental measure crack initiation angle of 8 mm thickness is much smaller than the value calculated by two-dimensional fracture criterion. It is necessary to develop a new universal three-dimensional mixed mode fracture criterion that is nearer the truth. |
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