Effect of form defect on pipe surfaces subjected to pressure at the assembly point

Abstract

Shrink-fit assemblies have been used to offer a more robust running surface for wooden wheels for a long time. Generally, the two parts are cylindrical or conical. Shrink-fit is now an operation that involves creating contact between two cylinders, there is no third party, and this is good economically. It’s employed in a variety of industries, including automotive, aerospace, oil and gas, and train wheels. To do this operation, the inner cylinder’s outer radius must be greater than the outer cylinder’s inner radius, that difference between them is called “interference,” the latter is being important in the assembly because it contributes to increasing the resistance of the assembly. There are three ways to do this: the first by heating the outer cylinder until it expands, the second by cooling the inner cylinder until it shrinks, and the third way is to realize the fitting under a press. When two cylindrical components are assembled by pushing or shrinking one onto the other, at the interface between the two matching parts, a contact pressure and friction force is formed. In this paper, we study shrink-fit assembly consisting of two thin hollow cylinders with the inner cylinder subjected to pressure, this actually represents what happens to the tubes at the assembly point (where the tube meets the other), taking into account that the surfaces are not perfect but are wavy, meaning they contain form defects. Using numerical simulation, we want to know the effect of the form defect on the distribution of stresses, deformations, and assembly resistance, and is this effect positive? or not.