عنوان مقاله [English]
Many engineering components are subjected to cyclic loading which is the main cause for most of engineering failures. When a cyclic loading is repeated, fatigue must bring into account for any life estimation study. Fatigue results in failure of the engineering components in a stress level well below the yield stress of the material. Life extension techniques can delay the initiation or
propagation of the crack in the engineering structures. Most of these techniques induce compressive residual stresses which can enhance the component fatigue life. As the crack usually starts from the surface, the induction of compressive residual stresses on the surface of the components can greatly influence the component life cycle. There are many surface modification techniques practicing in different industries. Shot peening is one of the most well-known surface treatment methods that is employed to enhance the fatigue life.In the current paper, severe shot peening has been applied to samples made of Aluminum A356. This alloy has been used where high strength, good weldability, ability of permanent die casting and corrosion resistance are required. A356 is an aerospace aluminum alloy and has a wide application in other industries, such as automobile and military. Fatigue crack growth and life curves of as-received and shot peened samples have been found both numerically and experimentally. Finite element analyses of the shot peening process are still under development by many researchers. The exact coverage percentage is difficult to achieve, and it requires simulation of a random peening process. This manuscript also describes how to achieve the correct coverage. The experiments were designed very carefully to evaluate the effects of the shot peening process. Very good agreements were observed between results. They showed life extension for high cycle fatigue up to three times. Having the finite element results in hand, the experimental achievement was explained.