| Project/Area Number |
15360121
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Dynamics/Control
|
|---|
| Research Institution | Yokohama National University |
|---|
Principal Investigator |
MORISHITA Shin Yokohama National University, Graduate School of Environment and Information Sciences, Professor, 大学院・環境情報研究院, 教授 (80166404)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIRAISHI Toshihiko Yokohama National University, Graduate School of Environment and Information Sciences, Assistant Professor, 大学院・環境情報研究院, 講師 (30361877)
|
|---|
| Project Period (FY) |
2003 – 2005
|
| Project Status |
Completed (Fiscal Year 2005)
|
| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2004: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2003: ¥5,000,000 (Direct Cost: ¥5,000,000)
|
|---|
| Keywords | Vibration / Friction Vibration / Vibration Control / Magnetorheological Fluid / Absorber / Dynamic Design / 振動騒音 / 摩擦機構 / 衝撃応答 / 騒音制御 / 可変減衰 / 準能動制御 |
|---|
| Research Abstract |
This research deals with the vibration and noise reduction induced by the friction between surfaces of elastic structures. It is well known that the friction force may induce self-excited vibration in dynamic systems caused by the apparent negative damping of the system. Once it happens, it is very difficult to reduce the amplitude of vibration and it is sometimes followed by the destruction of the system itself. In the case when there is no destruction of the system, it makes large noise uncomfortable for the people around it. So it is important to study the mechanism of friction vibration to reduce its amplitude and noise.
Self-excited vibration and stick-slip phenomena are main target of this study. Though stick-slip phenomenon is usually considered as self-excited vibration, they differ to each other. Stick-slip is typically caused by the difference of static friction force and dynamic one. On the other hand, self-excited vibration is defined to be caused by negative damping of the
… More
system. It may be confusing that stick-slip phenomena are sometimes found in the dynamic system having equivalent negative damping.
In order to avoid the stick-slip phenomena, one of the effective ways is to decrease the difference between the static and dynamic friction force. Automatic Transmission Fluid (ATF) has been developed for this purpose and various kinds of Friction Modifier (FM) are blended. Even applying FM to the system which has the possibility to show the stick-slip phenomena, it may be deteriorated after long interval. When the noise is caused mainly by the out-of-plane vibration of friction plates, it may be effective for noise reduction that the distance from the friction surface to the neutral plane of the plate should be decreased. The best condition is coinciding the two planes each other. This trial was conducted by small size model, and it showed remarkable decrement of amplitude of the friction plates. But it should be noted that the vibration energy was transmitted to the other elastic components of the system, and noise was made by other part of the system. In such cases, the vibration amplitude should be decreased by absorbers.
MR fluid is one of the functional fluids, and it has been successfully applied to controllable dampers. The investigators proposed to design MR devices considering the flow patterns of MR fluid in the mechanical components. As described above, one of the best ways for vibration and noise reduction is to apply dampers to the friction system, but the experimental verification of this idea to the system may be conducted in the near future. Less
|
