深潜器耐压球壳初始缺陷对极限强度作用机理及评估方法

The influence of initial imperfection induced by manufacturing technique on ultimate strength of submersible spherical pressure hulls is considered insufficiently during traditional approach is applied, as a result, the new ultimate strength assessment method taking account of complete initial imperfection induced by welding is proposed. On the basis of welded joint mechanical properties test for titanium alloy thick plate and welding stress and strain field analysis for spherical pressure hulls, correlation analysis of welding parameter with initial material imperfection and initial geometric imperfection is investigated. An innovative calculation model of spherical pressure hulls’ ultimate strength is adopted and analysis of numerical simulation results is combined as well, influence mechanism of welding initial imperfection on ultimate strength of submersible spherical pressure hulls is revealed. Additionally, the quantitative relationship between the parameters of welding energy, structural dimension, material properties and structural ultimate strength is taken into account as objective, and assessment method on ultimate strength of submersible spherical pressure hulls considering effect of complete initial imperfections is established through experimental and numerical results study. New idea is a significant supply to structural design of deep submersible spherical pressure hulls, which also has important reference value for ultimate strength assessment of other structures.

针对潜水器耐压球壳极限强度传统评估方法在考虑加工初始缺陷影响方面不充分，提出了新的全面考虑焊接所致初始缺陷影响的极限强度评估方法。以测试钛合金厚板焊接接头力学性能和钛合金耐压球壳焊接应力应变场分析为切入点，研究焊接工艺参数对材料初始缺陷和几何初始缺陷形成的相关性。通过引入新的耐压球壳极限强度计算模型，结合数值实验数据分析，揭示焊接所致初始缺陷对深潜器耐压球壳极限强的影响机理和规律。进一步，以量化焊接能量参数、结构几何参数、材料属性参数与极限强度之间关系为目标，通过数值方法和模型试验相结合，建立客观考虑加工工艺参数的深潜器耐压球壳极限强度评估方法。本研究为深潜器耐压球壳极限强度提供新的计算思路与评估方法，对于其他结构的极限强度评估问题也有重要的参考价值。

深海技术被认为是与航天技术、核能利用技术并列的高新领域，而载人深潜器则是海洋开发和海洋技术发展的最前沿和最高点。深潜器耐压球壳是载人深潜装备最为核心的技术之一，也是保障潜航员等深海作业人员生命安全的最核心部件，国际上现行的耐压球壳极限强度计算方法未能充分考虑加工工艺与深潜器耐压球壳材料、几何初始缺陷形成及对极限强度的影响。为此，项目创造性地提出了一种新的考虑焊接热影响区域等效材料属性的耐压球壳极限强度评估方法，通过开展焊接数值模拟方法验证、焊接热影响区域界定、热影响区域等效材料属性测定、加工工艺参数与初始缺陷相关性以及缺陷对结构极限强度影响等几个方面的研究，证实了本研究所提出的耐压球壳极限强度评估方法的可行性与有效性。并通过试验和数值结果分析，揭示了焊接所致初始缺陷对结构极限强度的影响规律，探索出了有缺陷的深潜耐压球壳剩余极限强度评估方法。.项目按照原定计划，严格按照经费使用要求列支，圆满完成所有研究目标。项目研究成果丰富，可广泛的应用与海洋装备耐压结构极限状态评估，也可拓展应用于焊接结构静态极限强度等问题的分析。