Research On The Test Method Of Hard-coating Structure Vibration Reduction

Using hard-coating to reduce vibration is proposed in recent years, so it is a new reach field. The hard-coating shows the perfect characteristics, such as thermostability and wear resistance, so compared with traditional viscoelastic coating materials, vibration reduction used hard coating has great technical advantages. Hard-coating materials usually show the property of strain-dependence, which leads to the hard-coating composite structure dynamic system become nonlinear of stiffness and damping. So the traditional test method, which based on linear vibration theory, can not satisfy the needs of hard coating vibration reduction design research. The focus of this study is on test method of hard-coating structure vibration reduction, which researches from two aspects:hard-coating composite structure damping test and the identification of hard coating material mechanics characteristic parameters. The main research contents of this paper are as following:(1) Aimed at the insufficient of traditional damping test method, the focus of this part is on free attenuation signal envelope method to identify hard-coating composite structure’s damping. The testing process, software system and hardware system of this method are described in details. At last, modal loss factor of a titanium thin plate is identified by tree attenuation signal envelope method.(2) The traditional bandwidth method is modified to make it be suitable for damping identification of hard-coating composite structure in frequency domain. The testing process of the modified bandwidth method is described. At last, take a titanium plate with NiCrAlY-coating as example. The modal loss factor of this structure is identified by the modified bandwidth method.(3) Considering the loss factor of metal substrate, the principle formula of vibration beam method is derived. The testing process of this method is described in details. Following this process, the mechanics characteristic parameters of NiCrAlY are obtained. (4) The strain-dependence of hard-coating material mechanics characteristic parameters is verified. Based on Euler-Bernoulli beam theory, a method, which can obtain strain-dependence elastic modulus and loss factor, is proposed. Then the scientific and feasible testing process is described. At last, according to the process, the strain-dependence elastic modulus and loss factor of NiCrAlY are obtained.This study can operate as a service for creating hard-coating composite structure dynamic model and vibration reduction optimization design. In addition, this study can also provide technical support for application of hard-coating vibration reduction technology in thin walled structure.