摘要
通过对比分析多种典型蠕变本构模型,考虑应力水平、本构模型、蠕变时间等三个因素的影响,确定了TC4ELI材料钛合金常温压缩蠕变本构方程及其系数,初步建立了钛合金耐压结构蠕变数值计算方法。对钛合金环肋圆柱壳模型开展蠕变数值计算,给出蠕变前后模型的应力、应变和位移的变化情况。结果表明:修正的时间强化模型可以表征钛合金耐压结构初始蠕变阶段和稳态阶段的蠕变特性,能够适用于深海钛合金耐压结构的蠕变计算;产生蠕变变形后钛合金耐压结构应力重新分配,高应力区范围有所扩大,蠕变后弹性应变和总应变均减小;相比于纵向,蠕变对环肋圆柱壳结构的径向变形影响更大。
The creep constitutive equation and parameters for TC4 ELI alloys at ambient temperature are confirmed by analyzing typical creep constitutive models comparatively, and creep numerical calculation methods for pressure structures of titanium alloy are established considering the effect of stresses, constitutive models and creep time. Creep numerical calculations of ring-stiffened cylindrical shell of titanium alloy are developed, and variations of stress, strain and deformation by reason of creep are presented. The results show that modified time hardening model could characterize the creep behavior of pressure structures made of titanium alloys in the stage of primary creep and steady-state creep, applicable to the creep calculation of pressure structures made of titanium alloys in deep sea. Redistribution of stress occurs after creep deformations develop in pressure structures made of titanium alloys, and the scope of region for high stress is enlarged, while there has been a decrease in elastic strain and total strain. Compared with the longitudinal direction, the creep has a greater influence on radial deformation of the ring-stiffened cylindrical shell.
引文
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