Influence of Ramberg–Osgood fitting on the determination of plastic displacement rates in creep crack growth testing
Influence of Ramberg–Osgood fitting on the determination of plastic displacement rates in creep crack growth testing
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Ramberg-Osgood 拟合对蠕变裂纹扩展试验中塑性位移速率测定的影响
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发表时间：
2007
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影响因子：
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通讯作者：
K. Yoon
中科院分区：
文献类型：
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作者：
N. Huh;Yun‐Jae Kim;K. Yoon
本文通过对标准紧凑拉伸试样进行详细的二维和三维有限元分析，研究了Ramberg-Osgood（R-O）拟合程序对蠕变裂纹扩展测试中塑性位移速率估计的影响。考虑了四种不同的R-O拟合程序：（i）拟合整个真实应力-应变数据直至极限抗拉强度，（ii）拟合真实应力-应变数据从0.1%应变至0.8的真实极限应变，（iii）拟合真实应力-应变数据仅至5%应变，（iv）拟合工程应力-应变数据。结果发现，前两个拟合程序可以产生显着的误差，在塑性位移速率估计。另一方面，后两种方法提供了相当精确的塑性位移速率，因此应推荐用于蠕变裂纹扩展试验。本文讨论了在5%应变范围内拟合工程应力-应变数据优于拟合真实应力-应变数据的几个优点。
This paper investigates the effect of the Ramberg-Osgood (R-O) fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite-element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered: (i) fitting the entire true stress-strain data up to the ultimate tensile strength, (ii) fitting the true stress-strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress-strain data only up to 5% strain and (iv) fitting the engineering stress-strain data. It is found that the first two fitting procedures can produce significant errors in plastic displacement rate estimates. The last two procedures, on the other hand, provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Several advantages of fitting the engineering stress-strain data over fitting the true stress-strain data only up to 5% strain are discussed.