2001 Fiscal Year Final Research Report Summary
Impact and friction mechanisms and structural changes of snow and ice in snow avalanches, ice blasts and icy planetecimal impacts
| Project/Area Number |
10490003
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | Hokkaido University |
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Principal Investigator |
MAENO Norikazu Hokkaido Univ. Prof., 低温科学研究所, 教授 (50001657)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Hiroshi Muroran Tech. Coll. Prof., 機械システム学科, 教授 (70002938)
ARAKAWA Masahiko Hokkaido Univ. Asso. Inst., 低温科学研究所, 助手 (10222738)
MIZUNO Yukiko Hokkaido Univ. Asso. Prof., 低温科学研究所, 助教授 (10002461)
TAKEI Iwao Hokuriku Univ. Lec., 薬学部, 講師 (70247477)
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| Project Period (FY) |
1998 – 2001
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| Keywords | Snow avalanche / Ice blast / Icy bodies / Impact Frictiont / Crack / Snow / Ice / Shock wave |
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| Research Abstract |
Ice-ice friction measurements were extended to the lowest sliding velocities aimed originally in the project. For the experiment a new device of non-rotation type was constructed and installed in a cold room, which enabled us to carry out the friction experiment to the velocities of 10^<-7> to 10^<-3> m/s and normal stresses of 123 to 368 kPa. The obtained results below 10^<-4> m/s was different f rom what has been expected from the traditional adhesion shear mechanism. Based on the experiment al result a new model of adhesion shear mechanism was proposed taking account of junction growth d ue to sintering of ice asperities on the sliding surfaces.
High speed impact experiments were conducted in relation to the formation mechanism of characteristic craters found on regolith layers on asteroids, Mars, and other icy bodies. Samples used are mixtures of H_2O ice, CO_2 ice and rocks, and projectiles, made of H_2O ice, metal or plastic, were impacted with a speed of 100 to 600 m/s. The project was conducted with cooperation of Prof. Leliwa-Kopystysnski of Warsaw University. Effects of electric field on ice friction were investigated.
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