Vibration Analysis And Optimization Of Composite Structure With Constrained Viscoelastic Layer Damping Treatments

With the wide use of viscoelastic material in engineering to control the vibration and the appearance of new viscoelastic material in recent years, the dynamic problem of viscoelastic complex structures becomes more and more important.In this paper, the first is a study on the modeling of the internal variable and a description of the temperature influence on the viscoelastic parameters. And then, using ISD 112 material as the example, a procedure is used to analysis the performance parameters and provide a better estimate of the curves at different temperatures, then minimizing the inaccuracies that could result from the curve-fitting of the material properties. Then learn the vibration models and governing equations of constrained layered beams that have multiple viscoelastic damping layers (2n-l and 2n layers of damping).A MATLAB program was developed using the equations developed above to find the loss factors and resonance frequencies of the multi-layered system. And the multi-objective optimization procedure to obtain optimum structural and material parameters corresponding to given temperature and frequency range for maximizing system damping. And through a case discuss the thickness, location of damping and elastic layers effects to the system's loss factor, frequency.And then, study damping of beams that have partial damping constrained layers. A parametric analysis is conducted to study the effects of different parameters on the damping and vibration response of the system under simply supported boundary conditions (such as the effects of layers thickness, location/length of partial constrained layer). And an objective optimization is also used to obtain optimum structural and material parameters. The object all of these is to reduce the vibration and noise of the structure.At the end, as the further discuss of above, the wave-number and speed of flexural wave propagating in sandwich beams are studied. The effect of thickness, elastic modulus and shear modulus on wave propagating in sandwich structures is analyzed.This paper studies the vibration response of the system under different boundary conditions, and different parameters. And get some value theory results in engineering.