Ti-6Al-2Sn-2Zr-3Mo-X为我国深海装备用新型高强度钛合金材料，准确掌握其在复杂应力状态下裂纹起裂扩展满足的力学条件及裂纹偏折规律，对于合理开展深海装备断裂力学评估，保障结构的服役安全性具有重要意义。开展基于紧凑拉伸剪切试样的Ti-6Al-2Sn-2Zr-3Mo-X材料I-II混合型裂纹断裂特性试验研究，揭示不同拉伸-剪切应力组合状态下新型钛合金裂纹起裂扩展条件和偏折规律。试验结果与经典断裂准则理论对比表明：拉-剪复杂应力状态下，新型高强度钛合金材料裂纹尖端临界距离上的最大环向应力达到材料断裂应力时，裂纹沿最大环向应力对应方向起裂扩展，即该钛合金材料拉-剪复杂应力状态下的裂纹起裂扩展可由最大环向应力准则预测。
The mixed-mode I-II crack fracture behavior of a high strength titanium alloy Ti-6Al-2Sn-2Zr-3Mo-X used in deep-sea equipment was investigated experimentally by compact-tension-shear (CTS) specimen based on the mixed mode crack testing system. It was shown that the high strength titanium alloy mixed-mode I-II crack propagation follows the maximum tangential stress (MTS) criterion. The crack propagates along the direction of the maximum tangential stress which reaches the critical stress $ {\sigma }_{\mathrm{c}} $ at the critical radius around the crack tip. Richard formulas were suggested for the fracture assessment of deep-sea equipment built by the high strength titanium alloy.
2022,44(16): 24-27 收稿日期：2021-09-06
DOI：10.3404/j.issn.1672-7649.2022.16.005
分类号：U661.4;O348
基金项目：国家重点研发计划课题资助项目（2017YFC0305500）
作者简介：黄如旭 (1987-)，男，高级工程师，研究方向为海洋工程结构疲劳与断裂理论、实验及数值仿真
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