Development and Design of New Magnetic Damper Based on Magnetic Seesaw Phenomen

本研究的目的是建立一种基于村上博士提出的“磁跷板现象”的新型磁振阻尼器的设计方法。这种磁阻尼器的优点是不仅具有减振能力，如微震动，而且具有减振能力，如大激励，如地震响应1。根据已建立的“磁跷板现象”设计准则，研制了3种试验型磁阻尼器，通过改变阻尼器的直线滑动步长来产生不同的磁阻尼力。采用正弦和随机两种输入方式进行了振动试验，考察了系统的减振频率特性。通过试验，确定了层合噪声的最佳设计条件、噪声与磁极的关系以及获得期望磁阻尼力所需的间隙宽度。并进行了理论研究。建立了基于“磁导”行为的数学模型，并将其应用于永磁体的设计中。利用该模型进行了数值仿真，对频域内的阻尼特性进行了评估。结果与测试结果相当吻合，至少在本研究项目采用的条件下是如此。未来要解决的问题是将这一研究发展到更一般的情况，即振动条件变得更加广泛，并且必须考虑减振装置中的摩擦和间隙运动等非线性效应。

The purpose of the research project is to establish a design method of a new magnetic -vibration damper based on a "magnetic seesaw phenomena" which was proposed by Dr. Murakami. The advantage of this magnetic damper is to possess a capability for reducing vibration not only small on such, as micro tremor but also large excitation such as seismic response.1. Based on the established design criteria due to "magnetic seesaw phenomena", 3 kinds of trial magnetic dampers were manufactured, each of which were designed to produce different magnetic damping capacity by changing a step length of linear sliding motion of the dampers.2. In order to examine the damping ― frequency characteristics, shaking test was carried out by sinusoidal and random input motions. Though the testing, optimum design conditions to the number of laminated yawks, the relation between yawks and magnetic poles and the gap width for getting the expected magnetic damping capacity were estimated.3. Theoretical investigation was also performed. Mathematical modeling was constructed based on "permeance" behavior which has been used in the design of the permanent magnet. Through numerical simulation by using this model, damping characteristics in the frequency domain were evaluated. The results quite well agreed with the testing results at least under the conditions adopted in this particular research project.4. Future problems to be challenged is to develop this research to more general cases whereby vibration condition becomes much more expanded and nonlinear effects such as friction and gap motion in the damping devices have to be considered.