防护结构设计中应变速率效应问题

DISCUSSION ON THE CONSIDERATION OF THE RATESENSITIVITY IN DESIGN OF PROTECTIVE STRUCTURES

在防护结构设计中，通常是采用材料的动力强度和动力弹性模量以考虑应变速率效应问题。应用所提出的应变速率相关材料模型，对核武器及常规武器爆炸作用下的钢结构和钢筋混凝土结构进行速率相关分析，并与考虑材料强度提高的速率无关分析对比。两种分析结果表明，对于钢结构，两种计算结果相差不大；而对于钢筋混凝土结构．两种计算结果相差较大，而且目前防护结构设计方法偏于保守。

In the current design manual of protective structures,the dynamic material strength and Young' s modulus are frequently utilized in order to take into account of the effect of strain rate on the structural response. Based on the proposed rate-sensitive material models, this paper undertakes the rate-sensitive analysis and rate-insensitive analysis (but considering enhancement of the material strength) of steel and reinforced concrete beams subjected to blast loads induced by nuclear or conventional weapon explosion. Comparison of the two analyses is given. It is observed that the two analyses have minor difference in the response of the steel beams,and significant difference in the response of the reinforced concrete beams. It is pointed that the consideration of ratesensitivity in the current design manual of protective structures may lead to be over- conservative when designing reinforced concrete structures.