Research On Vibration Of Rotary Viscoelastic Sandwich Beam

Higher demand for the efficiency of rotating machine has been put forward increasingly because of the high development of manufacturing. And rotor vibration caused by increasingly higher speed, has become a bottleneck to the stable operation of high speed rotors. As a result, the design and research on relieving vibration of rotor system is of great importance. Among common vibration-relief structures, viscoelastic damping sandwich has advantage of light weight, high strength, high specific stiffness and vibration and noise reduction. The researches on viscoelastic damping sandwich have mainly concentrated on plate, such as rectangular plates, circle plates, and so on. And the effects of rotation speed on such beams have been seldom reported. Based on theoretical analysis and numerical simulation, some research have been done on cylindrical viscoelastic damping sandwich beams.1) Based on the force analysis of rotary sandwich beams and the Kelvin-Voigt viscoelastic constitutive equation, vibration control equations were established while taking rotational inertia thickness and angular velocity into consideration, and expressions of kinetic energy and potential energy of the base, sandwich and constrained layers were deduced.2) The vibration characteristics of viscoelastic sandwich beam which expressed in static and rotational condition were studied and discussed. The expression of vibration mode function in static and rotational condition was obtained while solving the vibration control equations with separation of variables. The vibration control equation was discretized with method of Galerkin, and expressions of the natural frequency and loss coefficient of rotational sandwich beam was deduced with both ends simply supported, the free response of system was solved. Besides, the effects of sandwich beam’s size and angular speed on natural frequency and loss coefficient were studied.3) Based on numerical analysis of rotary viscoelastic sandwich beam and normal beam, the natural frequency, damping ratio and vibration mode were studied. And the effects of factors on natural frequency and damping ratio was discussed, including thickness and shear modulus of sandwich layer, constrained layer and its thickness and angular velocity.