Finite element prediction of the contact pressure distribution in a hydraulically expanded tube-to-tubesheet joint U.A. Abdelsalam, M.A. Dokainish Mechanical Engineering Department, McMaster University, Hamilton, Ontario, Canada L8S 4L7 Abstract The hydraulic expansion of the tube-to-tubesheet joints is modelled using a 2-D axisymmetric elasto-plastic finite element model. The contact interaction between the tube and the sleeve ishandled by an in-house contact algorithm. The residual contact traction and the joint structural strength are examined against the expansion pressure and the initial radial clearance. 1. Introduction The hydraulic expansion of tube-to-tubesheet joints isa common practice in the assembly of shell and tube heat exchangers. The basic idea of the expanding process isto deform the tube beyond the elastic limit while minimizing the plastic deformation of the tubesheet. Upon the release of the expanding force, the tubesheet material springs back more than the tube material exerting a residual contact pressure which holds the tube tight in the tubesheet hole. In terms of quality, the basic requirements of a successful joint are the leak-tightness and the low residual tensile stresses in the tube transition zone. On the other hand, a reasonable residual normal contact pressure is needed for the joint integrity. Despite its long involvement in diverse industrial applications, the expanded joint still presents a serious source of loss of production in the power industry in particular. This deficiency is a result of the lack of a well-defined design procedure which is based on a full understanding of the complex deformation processes involved inthe manufacturing and during operation. A detailed account of the related literature is provided by Abdelsalam and Dokainish [1]. Several experimental studies were conducted mainly to measure the holding force of the expanded joint against axial pull-out or push-in loads. Oppenheimer Transactions on Modelling and Simulation vol 10, © 1995 WIT Press, www.witpress.com, ISSN 1743-355X