For the service life of metal components and structures the surface and subsurface conditions are of decisive importance. That is the case in all industrial sectors where components are subjected to high stresses e.g. Automotive and Vehicle, railway, aerospace, steel and bridges, gear, combustion engines, steam and gas turbines, compressors and pumps manufacturing, tools, and medical equipment. This is mainly due to the fact that the damage processes, such as Fatigue and corrosion, are initiated at the surface and can thereby be delayed or accelerated, depending on the material condition and quality of the surface layer zone.
It has been known for decades that mechanical surface treatments such as shot peening, deep rolling and hammer peening improve the fatigue strength and extend the service life of components and structures. However in the industrial practice, it suffices often to determine the achieved fatigue life improvement by means of experimental investigations. If the achieved life was adequate for its intended purpose, generally no further optimization of the process would be carried out due to the costs of such experimental studies. Purely experimental investigations form a valuable body of knowledge for describing the surface material conditions and fatigue behavior. However Since there are quite a number of process parameters which could influence the surface conditions i.e. residual stress, work hardening and topography, application of the numerical methods are indispensable for utilizing material strength reserves by process optimization.
In this study numerical simulation of shot peening, deep rolling and hammer peening of metallic specimens will be presented and compared with experimental results. For some cases the numerically and experimentally determined fatigue life of specimens after mechanical surface treatment will be shown considering the effect of surface material conditions.
|Category||Short file description||File description||File Size|