@Article{sdhm.2012.008.295, AUTHOR = {S. Kwofie}, TITLE = {Relaxation of Residual Stress under Fatigue Load Described in Terms of Cyclic-Plastic Deformation Model}, JOURNAL = {Structural Durability \& Health Monitoring}, VOLUME = {8}, YEAR = {2012}, NUMBER = {4}, PAGES = {295--306}, URL = {http://www.techscience.com/sdhm/v8n4/35077}, ISSN = {1930-2991}, ABSTRACT = {Fatigue life of components may be enhanced by mechanical surface treatments, such as shot penning, which induce compressive residual stresses in the component's surface. Under cyclic/fatigue loads, however, relaxation of the residual stress may occur thus, reducing the optimum benefit of the surface treatment. For health monitoring / life prediction under such conditions it is important to be able to assess stress relaxation in real-time. However, the phenomenon of cyclic relaxation of residual stress is not well understood and its tracking during component operation is a technical challenge. By means of cyclic plastic deformation model and the Matlab/Simulink Program cyclic relaxation of residual stress is simulated. Simulated results show that residual stress relaxation under cyclic loading is associated with mean-strain shift, which is indicative of stress redistribution. The significance of this mean strain shift is briefly discussed in terms of tracking and quantitatively determining residual stress relaxation in real-time. Reduction in residual stress may be estimated as the product of mean-strain shift and the elastic modulus of the material.}, DOI = {10.32604/sdhm.2012.008.295} }