1994 Fiscal Year Final Research Report Summary
Lubrication properties of liquid crystal
| Project/Area Number |
05805014
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
設計工学・機械要素・トライボロジー
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| Research Institution | Inst. Industrial Science, University of Tokyo |
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Principal Investigator |
KIMURA Yoshitsugu University of Tokyo, Inst. Industrial Sci., Professor, 生産技術研究所, 教授 (20010910)
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| Project Period (FY) |
1993 – 1994
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| Keywords | tribology, / liquid crystal, / nematic, / lubricant, / hydrodynamic lubrication / boundary lubrication, / electric field, / electrorheological effect |
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| Research Abstract |
This project has been conducted to study the possibility of using liquid crystal as lubricant. Since some mechanical properties of liquid crystal films can be changed by applying electric fields, it is expected that friction characteristics can be actively controlled in both hydrodynamic and boundary lubrication regimes.
Viscosity is the key factor governing friction in hydrodynamic lubrication. Then viscosity of liquid crystal samples are determined on a rotational viscometer under varying shearing speed, electric field and temperature. Marked increase in apparent viscosity is observed for p-type nematic liquid crystals, showing an electrorheological effect. Further, continuum analysis employing a simplifying model is conducted, which gives theoretical prediction with reasonable accuracy.
Sliding experiments are conducted at an extremely low speed providing a boundary lubrication condition on a pendulum friction tester and a pin-on-disk friction tester. Decrease in the friction coefficient as large as 40% is observed by the application of a d.c. voltage up to 60V.
These results suggest possibility of active control of friction coefficient in practical tribological systems.
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Research Products
(6 results)
