Grant-in-Aid for Co-operative Research (A)
|Allocation Type||Single-year Grants|
|Research Institution||Osaka University|
KUBO Shiro Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (20107139)
AOKI Shigeru Tokyo Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (90016436)
MIYA Kenzo University of Tokyo, Faculty of Engineering, Professor, 工学部, 教授 (30011191)
KAGAWA Yukio Okayama University, Faculty of Engineering, Professor, 工学部, 教授 (10019200)
ABE Hiroyuki Tohoku University, Faculty of Engineering, Professor, 工学部, 教授 (00005266)
OHJI Kiyotsugu Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (20028939)
|Project Period (FY)
1990 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥9,300,000 (Direct Cost : ¥9,300,000)
Fiscal Year 1991 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1990 : ¥5,800,000 (Direct Cost : ¥5,800,000)
|Keywords||Inverse Problems / Non-Destructive Inspection / Crack Identification / Force Identification / Regularization / Boundary Value Identification / Boundary Element Method / Governing-Equation Identification|
Numerical-experimental hybrid inversion analysis schemes were developed and examined. Various kinds of domain/boundary inverse problems, boundary value inverse problems, force inverse problems, material properties inverse problems, and governing equation inverse problems were treated with special emphasis on regularization of the inversion analyses. The main conclusions obtained are summarized as follows.
1. Electric potential method was applied to the measurement of three-dimensional cracks and defects. From simulations and experiments it was found that the method can be applied to the measurement of cracks in small specimens. Efficient inversion schemes were developed, and assessment of their applicability was made. A method was proposed to estimate stress intensity factor using an A. C. electric potential reading.
2. Finite element. programming was made for analyzing eddy current electromagnetic fields. Its applicability to the measurement of cracks using eddy current was examined.
Electric current fields and temperature fields near cracks were discussed. Thermography was applied to the detection and measurement of defects.
4. Several schemes were proposed and examined for estimating displacements and tractions in contact region. Discussion was made on the ill-posedness of the boundary value inverse problems.
5. Estimation of boundary values in Galvanic Corrosion was made. Clustering techniques were applied and were found useful in the estimation. Optimization of cathodic protection was made.
6. Estimation of boundary values in transient heat conduction was made using boundary element discretization.
7. Source identification in wave equation was made using boundary element formulation.
8. Acoustic CT (computed tomography) was examined with several regularizing schemes. Schemes were proposed to estimate material properties of a discrete system.
9. A scheme was proposed for estimating governing equation from observations.
Proposed inversion schemes were applied successfully to treat various kinds of inverse problem. These are expected to give foundations for other inverse analyses. Less