Description of Residual Stresses in Autofrettaged Open-Ended Cylinders Made of High-Strength Steel

Abstract

The elastic range in loading–unloading processes is often reduced with a Bauschinger effect. This material property may have a high impact on residual stresses and, as a result, on the performance of autofrettaged cylinders under service conditions. The objective of the present paper is to demonstrate this impact using a material model that accounts for the response of typical high-strength steel. The solution is semi-analytic and, therefore, can be used for fast and accurate analysis of the process of autofrettage. A numerical example illustrates the general solution. This example shows that the Bauschinger effect has a significant impact on the residual circumferential stress in the vicinity of the inner radius of the cylinder. This stress is the most significant quantity of autofrettaged cylinders. Therefore, the main result obtained suggests that even a moderate Bauschinger effect should be taken into account in analyses of the process of autofrettage.

The Bauschinger Effect Magnitude Control in Ultra-Low Carbon Steel Wires

“…This phenomenon is considered harmful for most steels 8,9,10 , since these mechanical property changes occur without their magnitude being controlled. In contrast, once the intensity of this phenomenon is controlled, it is possible to use it to adjust the final steel mechanical properties, such as yield strength, tensile strength, and uniform elongation.…”

Cold Expansion Process with Multiple Balls—Numerical Simulation and Comparison with Single Ball and Tapered Mandrels

“…Different industrial sectors developed a range of processes for the generation of residual stresses. Autofrettage of thick-walled cylinders has its industrial applications (e.g., gun barrels or high pressure vessels) and it has been deeply studied [5][6][7][8]. In the specific case of the aerospace industry, the focus was centered on fasteners and bolts holes, where Boeing Company developed the first application of the mechanical autofrettage in aircraft airframes: the cold expansion process.…”