탄소성 표면의 표면 거칠기에 따른 접촉소음해석

Abstract

Although the economic damage is great in the event of a failure, the importance of indirect condition monitoring using sound emission is increasing in areas where direct measurement is difficult. AE plays a role in diagnosing mechanical aging through surface roughness and surface wear prediction. Against this importance, many researchers have pursued theoretical modeling of AE. It was found that gear meshing of the contacts of the protrusions is the main cause of AE generation. In this paper, the contact noise generated when a sphere moves relative to a surface having surface roughness of various heights was numerically analyzed using a deterministic technique. In consideration of the deformation of the surface, the following conclusion was obtained by applying the method of calculating the noise level within the audible frequency based on the elastic energy generated during the elastic restoration of the protrusion.In the case of a surface with Ra = 0.01 μm, it can be seen that the contact pressure and contact area increase as the load increases, and even under the condition of a load of 100N, the maximum contact pressure was 2.1GPa or less, which is the limit of plastic deformation. It was found that the maximum contact pressure reached the limit of plastic deformation for all surfaces with Ra = 0.1 μm or more, and it can be seen that the plastic deformation contact area increases as the surface becomes rough and the load increases. A surface with Ra = 1 μm shows a plastic deformation rate about 1.5 times higher under all load conditions than a surface with Ra = 0.1 μm, and a surface with Ra = 5 μm has a plastic deformation rate almost similar to that of the surface with Ra = 1 μm. Compared to a surface with Ra = 0.01 μm, the maximum noise value for a surface with Ra = 0.1 μm or more increased by about 15 dB at 10 and the noise level increased as the load increased. In this paper, since only the vertical displacement of the protrusion was considered, it was found that the effect of the noise level by the friction force was not significantly shown. In this study, the effect of contact noise due to surface roughness was examined using an analytical method based on the elastomeric deformation of the protrusion, and it is believed that the optimal surface for low noise of the machine driving unit can be presented through experimental verification in the future.