Numerical analysis of compressive residual stresses in metallic materials as a result of shot peening

Gamiet, Nadeem

Numerical analysis of compressive residual stresses in metallic materials as a result of shot peening

Master Thesis

2015

Publisher

University of Cape Town

Department

Department of Mechanical Engineering

Faculty

Faculty of Engineering and the Built Environment

Abstract

Of significant importance to the design, manufacture and maintenance of turbine components is the fatigue life thereof when subjected to variable loading conditions. Research and practical implementation has shown that shot peening considerably increases the fatigue life of a component by introducing compressive residual stresses within the surface layers of the component. This has created a need to develop a numerical model that accurately predicts such residual stresses produced from shot peening. This thesis offers a simplified numerical model depiction of the shot peening process on a target material. A Finite Element based software (ABAQUS) model was employed to simulate the material behaviour and elastic-plastic deformation a metallic material undergoes during shot peening. An experimental platform was established by performing shot peening on material specimens while varying certain shot peening parameters. These parameters included shot size, shot velocity (related to a change in nozzle discharge pressure) as well as standoff (distance between exit nozzle and target material). The experimental data provided the stress profiles both on and beneath the target material surface layers and aided in the model development. Of specific interest was the magnitude of the maximum compressive residual stress developed just below the surface of the material and the depth of the compressive layer formed within the surface layers of the target material.

Keywords

Mechanical Engineering

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