At present, a cylindrical pressure vessel is most widely used in petrochemistry and other trades. Because of a sudden charge of curvature at the joint between head and barrel, a considerable edge stress will produce at this joint. Under the combined action of edge stress and primary membrane stress, the strength and service life of the device will be affected directly. Therefore, the research on edge stress has certain value and significance for engineering design and the use of the device. For this purpose, we have measured the stresses of a typical pressure vessel and analysed synthetically measured result. The distribution law of the total and edge stress around the edge of a cylindrical pressure vessel is given by research on measurement of edge stress in pressure vessel. Therefore, related basis is provided for engineering design and effective method for reducing edge stress. The conclusion is drawn as follows:
Mutual superimposing results of edge stress and membrane stress make fairly total stress at edge reduce, so edge stress need not be specially considered for this kind of vessel in engineering design. But for brittle material of bad plasticity, the edge stress must be considered.
When welding seam at edge area has defects, inside stress of local material will remarkably go up. When there is a blowhole in welding bead, whose long axis is 2 mm and small axis is 1 mm, by calculation, tip stress of blowhole is as five times as that of no blowhole's tip.
The effective methods for reducing edge stress is provided in this article.
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 2, pages 863 - 866 Publisher:Ashgate Publishing Company
NDTnet
