2005 Fiscal Year Final Research Report Summary
In Vivo Strain Field Measurement for Biological Soft Tissue
| Project/Area Number |
16560061
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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 |
Materials/Mechanics of materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YOSHIKAWA Nobuhiro The University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (70230696)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Solid Mechanics / Computational Solid Mechanics / Biomechanics / X ray CT / Material Test / Image Processing / B-spline / Inverse Problems |
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| Research Abstract |
This study is a trial to restructure the framework of material testing for biological soft tissues. An image-based technique utilizing X-ray CT is investigated to identify three-dimensional displacement field followed by non-invasive observation of mechanical behavior.
Methodology : Two image data sets are constituted by laying up the cross-sectional tomograms taken under unloaded and loaded conditions. Assuming the displacement field is fairly represented by B-spline functions, we set an inverse problem to identify unknown parameters included in the function. A tentative displacement field is given by tentative values of the unknown parameters prior to the identification procedure. The identification problem is formulated so as to minimize error in terms of intensity difference between actually deformed image and virtually deformed image by following tentative displacement field.
Efficiency Enhancement : The constraint of incompressibility is added as a penalty function for the uniqueness of displacement field solution to construct modified objective function. The successive linearizations and solutions are performed by means of the Levenberg-Marquardt method. Parametric study is carried out to investigate strategy to determine the parameters to control solution search.
Parallel Computing : The solution algorithm is developed for utilizing parallel computing to enhance computational efficiency. The efficiency is drastically improved by virtue of locality of B-spline functions. The validity of the proposed method is demonstrated through an experimental example.
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