Dynamic Modeling And Analysis Of Viscoelastic Composite Beams

The mechanical system noise and vibration reduction has increasingly become the fo-cus on research. Viscoelastic material has better damping characteristics, and it plays an important role in the device’s noise and vibration reduction. So it makes the viscoelastic damping materials been widely used. As the viscoelastic material elastic modulus and the loss factor has the frequency and temperature dependence, so the dynamic characteristics of the calculation caused certain difficulties. Paper focus on the composite structure of viscoe-lastic damping dynamic calculations to study and validate for solving practical problems.This paper firstly analyze the naked beam with the finite element analysis to determine what kind of element type to use during the analysis of viscoelastic composite structures. In the analysis, the BEAM element, SOLID element and SHELL element are used in the mo-dal analysis, and have the comparison between the modal analysis and the dynamic test.Secondly, the characterization of the viscoelastic material is discussed. Viscoelastic material model assumes the linear viscoelastic model. By using the finite element analysis software ANSYS, the analysis is the fitting viscoelastic materials time domain of relaxation modules-the time data. For the transient analysis of viscoelastic composite structure, the Prony series and Maxwell units form were used to calculate with more consistent results.Thirdly, dynamic calculation is done to the composite beam with pasted rubber. Taking into account the frequency dependence of viscoelastic material, the paper ignored the tem-perature dependence of the viscoelastic material characteristics. Using modal strain energy iteration method for solving each order of natural frequency and loss factor of the composite structure. Yet the comparison between the finite element solution and the exact solutions has good consistence. An example shows the rationality and effectiveness of the method. Dis-cussion of viscoelastic material thickness of the structure have an effect on the natural fre-quency and the loss factor. Obtained some useful conclusions provided for the optimal damping treatment. Finally, vibration test is done to the composite beam. The test method are hammer modal test and electromagnetic vibration exciter with the sin-swept test. Obtained the natu-ral frequency and damping of the composite structure by hammer testing method. Use elec-tromagnetic vibration exciter with consistent force amplitude of sin-sweep function test the vibration reduction of the composite structure. Through the test, the structure pasted viscoe-lastic rubber can significantly reduce the resonance peak, and achieve good vibration reduc-tion.