Experimental Research On Dynamic Characteristics Of Non-Obstructive Particle Damping Elements

Earthquake is a huge natural disaster against human life and property. With the development of researches on the structural damping control and application, new ideas and new methods are attracting more and more attention. The effectiveness to withstand earthquakes is often constrained by changes in the natural period of structures; however, it is able to resist earthquakes in a broader frequency range to effectively increase the overall damping property of structures.Non-Obstructive Particle Damping (NOPD) is a new kind of damping technology, developed on the basis of the impact particle damping technology and the traditional particle damper technology since 1990s. It is applicable to the poor environment, with good damping characteristics and excellent damping effect. It means that an appropriate amount of metal or non-metallic small particles are filled to existing already or processed holes of the structure, in the transmission path of the vibration. During the vibration of structure, the momentum exchange and the vibration energy consumption occur through the collision and friction between particles to achieve the objective of damping. NOPD has many advantages: such as, small changes to the original system, almost without additional quality, significant increase in the damping of structure, applicability to the poor environment, and constant damping performance over time etc. In this paper, experimental studies will be made on Non-Obstructive Particle Damping elements, mainly in the following areas:1. For a single DOF system, the influence of particle type, particle filling rate and cavity shape on the dynamic characteristics such as damping and frequency are investigated through experiments. Cylindrical or rectangular cavities are adopted in the experiments. The results of dynamic characteristics are obtained for the application of two different kinds of particles, four different particle filling rates, two forms of cavity shape and two vibration directions. The fitting analysis is performed on the damping property.2. For a two DOF system, the influence of particle type and particle filling rate on the dynamic characteristics such as damping and frequency are investigated through experiments. The results of dynamic characteristics are obtained for the application of two different kinds of particles and five different particle filling rates. The fitting analysis is performed on the damping property.3. For three column specimens, the influence of particle type, particle filling rate and particle filling scheme on the dynamic characteristics such as damping and frequency are investigated through experiments. The results of dynamic characteristics are obtained for the application of three different cavity structures, six kinds of particles, and three or six different particle filling rates. The damping results are compared between those of the same particle diameter, those of the same type of particle but different particle diameters, and those of the same type and diameter of particle but different filling schemes. The optimal scheme of particle filling in columns is acquired.4. For the framework structure, specimens, the influence of particle type, particle filling rate and particle filling scheme on the dynamic characteristics such as damping and frequency are investigated through experiments. The comparisons are made between the two types of particles, three kinds of particle filling schemes, and three different filling rates. The optimal scheme of particle filling in the framework structure is acquiredIn this study, comprehensive studies are made on the non-obstructive particle damping elements and structures. The effective particle schemes are provided for the practical application of engineering.