Stress relaxation and elastic follow-up using a stress range-dependent constitutive model


          

刊名：Proceedings of the Institution of Mechanical Engineers
作者：J. T. Boyle（Department of Mechanical and Aerospace Engineering, University of Strathclyde）
刊号：780C0002-C
ISSN：0954-4062
出版年：2012
年卷期：2012, vol.226, no.6
页码：1472-1483
总页数：12
分类号：TH11
关键词：Creep；Power-law breakdown；Structural analysis；Stress relaxation；Elastic follow-up；High-temperature design
参考中译：
语种：eng
文摘：Despite the availability of detailed non-linear finite element analysis (FEA), some aspects of high-temperature design can still be best addressed through more simplified methods. One such simplified method relates to the problem of elastic follow-up where, typically in strain-controlled situations, elastic behaviour in one part of a structure can lead to large strain accumulation in another. Over the past 30 years, it has been shown that in regions with significant elastic follow-up, a plot of maximum stress against strain (a 'stress-strain trajectory') is virtually independent of the constitutive relation - a characteristic which can be used to estimate elastic follow-up for design purposes without detailed non-linear FEA. The majority of studies which have reported this independence on material behaviour have used simple constitutive models for creep strain, primarily based on power-law creep or variations. Recently, studies of the behaviour of high-temperature structures with a stress range-dependent constitutive law have begun to emerge. This article examines the problem of elastic follow-up using such a constitutive law for a classic two-bar structure and for a more complex structure using FEA. It is found that the independence of the stress-strain trajectory on constitutive equation is lost with a stress range-dependent relation.



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