A. Wisbey, P. H. Tranter, J. W. Brooks, QinetiQ Ltd, Farnborough, United Kingdom; Z. Hu, QinetiQ Ltd., Farnborough, United Kingdom

Summary:

Low plasticity burnishing (LPB) process is emerging as a promising surface treatment technology. It introduces a deep layer of high-compression material using a smooth, free-rolling ball moving in parallel passes on the surface of component in a pattern. The process can significantly improve resistance of components to wear and stress corrosion which may be particularly beneficial in enhancing the fatigue strength of critical, highly-stressed aerospace components like engine blades.

This presentation describes modelling the LPB process using 2-D and 3-D finite element methods. Because of the shape of the tool (ball) and the effects between adjacent passes, full 3-D analysis is necessary to model the process. However 2-D analysis has also been used because of its simplicity and it allows a parametric study of the process parameters to be carried out. The calculated residual stresses are found to be compressive in the sub layer of the LPB treated surfaces and the values agree well with those measured experimentally using X-ray diffraction methods.