DEVELOPMENT OF TECHNIQUE FOR DAMPING CAPACITY IMPROVEMENT BY COMPOSITE SURFACE STRUCTURE

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Sheet structures in machines often vibrate violently during operation. Some techniques for damping capacity improvement to prevent such vibration are developed in this research. They are very simple and do not require much money.Firstly, a differential equation system representing a structure model in which double-sided adhesive tape is applied on sheet surfaces is introduced. Here, a free dumped vibration is treated. From the solution of this equation system, the effectiveness of applied adhesive tape on damping capacity improvement is proved and the characteristic of the applied adhesive tape is clarified. An important characteristic of applied adhesive tape is the resistance against shearing deformation. We named this characteristic as shearing strain velocity coefficient (SSVC).Then, damping characteristic of actual sheet structures is measured and its improvement by adhesive tape application is recognized in experiment. By combining both the experimental and theoretical results, S … More SVC can be estimated. Such estimation is obtained in the dynamic state of the model structure.Some experiments to clarify SSVC directly have been carried out. Only a characteristic value for static state is obtained, because a small shearing strain velocity range is realized in our experimental apparatus. However, good linearity between the dynamic estimation and the static estimation is recognized. It is clarified that an adhesive tape having large static SSVC is effective for large damping capacity improvement.Above results are obtained in indicial response test. Then, the effectiveness against forced vibration is separately examined. Structure directly contacts the accelerating point, and friction force acting on this point has a large influence on the level of damping capacity improvement. It is clarified that damping capacity is slightly improved also in forced vibration.In the last experiment, the effectiveness of electroless plating film on damping capacity improvement is examined. Any types of electroless plating film can improve damping capacity. Damping capacity is greatly improved by the plating film dispersed with hard foreign small particles such as SiC. Less