Investigation of the compressive residual stress methods for improved fatigue life - TC6

Description Structural fatigue life can be improved significantly by applying compressive residual stresses on the highest stressed surfaces of a part. There are several methods used in the industry to achieve the compressive residual stresses, such as the shot peening, autofrettage (AF) or low plasticity burnishing (LPB) processes.This project will review the literature on the current technologies and methods used. The autofrettage and low plasticity burnishing will be explored in deeper detail, particularly where they are used in combination. The fatigue analysis methods and the effect of the mean stress on the fatigue life will be investigated in order to explain the benefit of the compressive residual stresses.The finite element analysis will then be used to simulate the AF and LPB methods in order to estimate the compressive stresses and the dependence on the process parameters, such as the applied pressure, as well as the materials used. A pressure component will be modelled as a case study to show the fatigue life improvement. Key Objectives Literature review on compressive residual stress methods.Investigation of the fatigue analysis methods and the effect of the mean stress.Autofrettage and low plasticity burnishing background study.Simulation of the AF and LPB processes using the finite element method and benchmark problems.Development of a case study of a pressure component such as a positive displacement pressure pump.