| Project/Area Number |
21540161
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic analysis
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| Research Institution | Ibaraki University |
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Principal Investigator |
SOGA Hideo 茨城大学, 教育学部, 教授 (40125795)
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| Co-Investigator(Renkei-kenkyūsha) |
TANUMA Kazumi 群馬大学, 工学部, 准教授 (60217156)
KAWASHITA Mishio 広島大学, 理学研究科, 准教授 (80214633)
SHIROTA Kenji 愛知県立大学, 情報科学部, 准教授 (90302322)
UMEZU Keniciro 茨城大学, 教育学部, 准教授 (00295453)
UMEHARA Morimichi 茨城大学, 大学教育センター, 准教授 (40532164)
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| Project Period (FY) |
2009 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2011: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2010: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2009: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 関数方程式 / 弾性方程式 / 偏微分方程式 / 逆問題 / 散乱波 / 弾性波動方程式 / 散乱問題 / 複素積分 |
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| Research Abstract |
The purpose in this research is the following : (1) to develop a new representation of elastic waves and to apply this to inverse problems;
(2) to investigate fundamental properties of elastic waves connected with the inverse problems.
The above (1) is an attempt to develop a primitive idea obtained previously into a detailed form. Although we have encountered an unexpected serious difficulty in this attempt, we succeed finally in proving the conjectured conclusion, and moreover make relation clear between the obtained representation and the known ones. Also we obtain an algorithm for an inverse problem to measure pre-stress from data of surface waves (Rayleigh waves) expressed by the representation. This is based on a formula which shows how the pre-stress depends on the velocity of the Rayleigh wave.
Concerning the above (2), we get new pieces of knowledge about the energy of waves. The one is verification that the energy propagates essentially along the characteristics. The other is precise estimation for influence of the dissipative terms to the energy decay. We show also the representation in (1) is useful to prove the Huygens principle for more extensive classes than previously known. Further, we have tried to prove the unique continuation property for the general elastic equation, as was planned, and get an idea for the proof. However, we do not accomplish this proof expected first.
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