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大量试验结果表明,结构钢会在高温下发生蠕变,然而由于蠕变试验数据不足且ASTM A992钢缺少相应的本构模型,数值分析时暂难以将高温蠕变考虑在内。最近发表的ASTM A992钢(Morovat等,2012)的蠕变数据缓解了试验数据不足的问题,为此建立了高温蠕变模型,重新研究材料发生蠕变的内在物理机制,并对高温蠕变模型的框架进行了讨论。采用双曲正弦模型对ASTM A992钢的蠕变试验数据进行拟合,并给出相应的最佳拟合参数。最后,对ASTM A992钢柱的高温蠕变屈曲进行研究,结果表明,蠕变起到十分重要的作用(尤其是在高温和荷载作用下)。
Numerous experimental results show that structural steels creep at high temperatures, however, due to insufficient data on creep tests and lack of corresponding constitutive models for ASTM A992 steels, high temperature creep is difficult to take into account during numerical analyzes. The recently published creep data from ASTM A992 (Morovat et al., 2012) alleviates the problem of insufficient test data. For this purpose, a high-temperature creep model was established to re-investigate the intrinsic physical mechanism of material creep. The framework was discussed. The hyperbolic sine model was used to fit the creep test data of ASTM A992 steel and the corresponding best fitting parameters were given. Finally, the high temperature creep buckling of ASTM A992 steel was studied. The results show that creep plays a very important role (especially under high temperature and load).