Analytical Modelling of Elastic-Plastic Interference Fit Joints

Abstract

The interference fit is a widely process, used to produce a joint assembly of two parts achieved by friction. It is a popular type of joint in machine elements and it is found in many field applications related to the automotive, aerospace, oil and gas and shipbuilding industries. Consequently, a better understanding of its limit behavior together with an accurate evaluation of the residual stresses generated by this process are very important for the design of mechanical components requiring high optimized performance. This work focuses on the analytical development of the residual stresses when the two assembled parts are circular cylinders and deform elasto-plastically under plane strain condition. The constitutive law that governs their material strain hardening behavior is assumed to follow a general power law which also covers the particular cases of elastic perfectly plastic and bilinear hardening. To validate the developed analytical model (AM), the finite element method (FEM) was used and the results showed good agreement between the two approaches. The obtained results show that the stresses increase when the interference value increases causing maximum stress intensity at the inner surface of the two assembled parts to exceed their material yield stress. After hollow shaft plastic collapse, any increase in interference results in a small increase in residual contact pressure with a large increase of the equivalent stresses localized at the hollow shaft inner surface. The method could be used to determine the maximum value of the interference in order to prevent assembly failure.
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