Buffer Action of Fluid Films

液压设备广泛应用于大功率机械设备的自动化、高性能运行。然而，对振动和噪声的降低也提出了要求。本研究的目的是为了阐明流体薄膜的缓冲作用和弹性变形。在第一个循环(1990)中，我们进行了理论分析。理论模型是圆柱体通过流体膜撞击悬臂梁表面的情况。我们独立地考虑了流体的粘度、可压缩性和悬臂梁的弹性变形和挠度的变化。在本研究中，缓冲作用的效率主要通过反弹系数的变化来评价。当撞击速度较小时，油膜厚度较大时，回弹系数变小。考虑到悬臂梁的偏转，薄膜的缓冲作用的效率随着薄膜的出现而变得清晰。在FINA…中更多的L循环(1991年)，我们从实验上检验了缓冲作用。圆柱体(8.5g，半径=4.5 mm)和球体(8.35g，半径=6.35 mm)通过流体膜撞击悬臂表面(钢，长180 mm，宽36 mm，厚16 mm)和无限大弹性体。通过用回弹系数估计缓冲作用，面接触比点接触能获得更大的缓冲作用。结果表明，液膜厚度越大，缓冲作用越大，悬臂梁的缓冲作用总体上越大。此外，对于圆柱体的情况，我们还将其与理论和实验结果进行了比较。他们在定性上对反弹系数有很好的一致性，但在数量上却不一致。对于悬臂梁的挠度情况，两者吻合较好。总之，利用流体膜和弹性变形来吸收冲击是可能的，并通过理论分析来估计其影响。较少

Hydraulic equipment is widely used for automation and high-performance operation of high-power machines and equipment. However, it is demanded to reduce the vibration and noise. The purpose of this study is to clarify the buffer action of fluid films and elastic deformation.In the first circular (1990), we carried out theoretical analysis. The theoretical model is the case that a cylinder impacts the surface of a cantilever through fluid films. We consider the changes of viscosity an compressibility of the fluid and the elastic deformation and deflection of the cantilever, independently. In this study, the efficiency of the buffer action is mainly evaluated by the changes of the coefficient of rebound. For the case where the impacting velocity is relatively small and the film thickness is comparatively large, the coefficient of rebound became small. Considering the deflection of the cantilever, the efficiency of the buffer action of films becomes to be clear with thin films.In the fina … More l circular (1991), we examined the buffer action experimentally. A cylinder (8.5 g, radius = 4.5 mm) and a sphere (8.35 g, radius = 6.35 mm) impacted the surface of the cantilever (Steel, length = 180 mm, width = 36 mm, thichness = 16 mm) and the infinite elastic body through the fluid film. By estimating the buffer action with the coefficient of rebound, the area-contacting is able to obtain larger buffer action than the point-contacting. It is clarified that the larger the fluid film thickness, the larger the buffer action, and as a whole the buffer action becomes larger by the cantilever. Furthermore, we compared with the theoretical (in the last circular) and experimental results for the case of the cylinders. They have good agreements for the coefficient of rebound qualitatively but do not quantitatively. For the case of the deflection of the cantilever, they have good agreements.In conclusion, it is possible to absorb the impacts by use of the fluid films and the elastic deformation, and estimate the effects by the theoretical analysis. Less