Noise reduction of rotating machinery by viscoelastic bearing supports.

摘要: The demand for silent rolling bearing applications, such as electric motors and gearboxes, has resulted in an investigation of viscoelastic supports. By placing a thin layer between the outer ring and surrounding structure, vibrations shaft-bearing arrangement can be isolated and damped way that radiated sound power is reduced. ultimate goal this research was to develop design strategy for supports resulting effective noise reduction. This thesis describes dynamic acoustic behaviour bearing applications with supports. Ultimately, investigations cover wide range aspects mechanical engineering: (1) description material behaviour; (2) development new Component Mode Synthesis method viscoelastic components; (3) experimental investigations into properties viscoelastic materials; (4) advanced structural models rotor dynamics applications; (5) numerical acoustic behaviour motor; (6) strategy reduction by viscoelastic bearing supports In present research, elastic components, like shaft or housing, and support are modelled finite element method. In addition, reduced save computation time. Viscoelasticity is described generalised Maxwell representation suitable both time frequency domain analyses. Viscoelastic materials measured on Dynamic Mechanical Analyzer to obtain dependent stiffness damping characteristics. The modelling approach succesfully validated at component level sandwich rings. results showed significant amount of damping can created layer. As next step, studies were performed a rotor test rig. A clear vibration achieved with viscoelastic supports, especially high running speeds. Subsequently, electric motor analysed. analysis based boundary element using so-called radiation modes. agreement between experimental satisfactory noisiest frequency range from 1000 2500 Hz. It found level the electric motor 3 5 dB(A) bearing support. Finally, proposed designing reducing bearing supports. set qualitative rules more quantitative design approach presented.