Behaviour of Metallic Thick-Walled Cylindrical Vessels or Tubes Subject to High Internal or External Pressures at Elevated Temperatures

Abstract

An analysis of the stresses and strains in a thick-walled cylinder, under internal and external pressure giving rise to purely elastic strain, was made initially by Lamé (1)† and subsequently several authors have dealt with the same problem. An analysis of stress and strain in similar cylinders at elevated temperatures, in which creep strain was regarded as being of major importance and the elastic strain of relatively trivial significance, was made by Bailey (2). This analysis has been much used by engineering designers. However, in practice cylindrical pressure vessels or thick-walled tubes may be subject at elevated temperatures to internal and external pressures in such circumstances that, over the whole or a considerable portion of the intended life of the structure, creep strains and elastic strains are both of significant order. Accordingly, it is obviously of practical importance that an analysis be made of the changes of distribution of stress and strain or strain rate with time, in such cases, and the current paper is directed towards this end. In the first portion of the paper, theoretical relations between stress, strain rate and time are derived, and in the second portion the application of these relations to a number of metallic alloys at temperatures within their practical working ranges is examined. A complete example of this application is worked out in detail for one material and temperature, as an aid to designers who may wish to use the methods described. It is to be emphasized that this work has become possible in view of the very considerable information regarding the complex stress-creep strain-time relations of a variety of engineering materials at elevated temperatures gained in the previous work of the authors.