深潜器多球交接耐压壳室温蠕变-疲劳特性研究

Study on Cold Creep-Fatigue Characteristics of Pressure-resistant Shells with Multi-sphere Junction for Deep-sea Submersibles

为了揭示钛合金深潜器多球交接耐压壳在实际作业过程中的蠕变-疲劳特性,通过定义的比例因子建立考虑蠕变损伤演化速率拉压不对称时的室温蠕变-疲劳损伤模型,通过对ABAQUS软件进行二次开发,基于蠕变-疲劳损伤模型和自动周期跳跃算法,建立了适用于深潜器多球交接耐压壳结构的蠕变-疲劳损伤数值模拟方法。数值分析结果显示,多球交接耐压壳结构的热点位置在承受拉伸载荷时,蠕变损伤对结构的蠕变-疲劳寿命影响显著,而承受压缩载荷时几乎不产生蠕变损伤;当作业水深增加时,蠕变-疲劳裂纹萌生寿命的减少速度明显高于疲劳裂纹萌生寿命的减少速度;当处于相同水深时,保载时间增加会使结构的蠕变-疲劳裂纹萌生寿命减少,但耐压壳的实际可作业时间大幅提升。研究结果可为多球交接耐压壳蠕变-疲劳强度的计算提供参考。

In order to reveal the creep-fatigue characteristics of the multi-sphere pressure shell of titanium alloy deep-sea submersible in actual operation,a creep-fatigue damage model at room temperature considering the tension/compression asymmetry of the creep damage evolution rate is established by constructing a scale factor.Secondary development of ABAQUS,which is based on the creep-fatigue damage model and automatic cycle jump algorithm,is carried out to establish the numerical simulation method of creep-fatigue damage.The numerical results show that the creep damage affects the creep-fatigue life significantly when the hot point of the pressure shell subjected to tensile load.There is almost no creep damage when the hot point subjected to compressive load.When the working depth increases,reduction rate of creep-fatigue crack initiation life is significantly higher than that of the fatigue crack initiation life.When the load hold time increases,the creep-fatigue crack initiation life of the pressure shell decreases,but the actual working time is greatly improved.The research results provide a reference for calculating creep-fatigue strength of multi-sphere pressure shell.