Indentatio with Punch by BEM/FEM Analysis and Image-sensing Method

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Three kind of new results are obtained in this report. First, this program for the combined analysis with BEM(boundary element method) and FEM(finite element method) is developed. The former has the merit for solving the large deformation and elastic-plastic problems in a narrow domain, and the latter for the elastic problems in a wide domain. This program is applied for the indentaffon by a circular punch, and there can be found the differences of the indentation force and the deformation of the specimen between a small and a large size of the specimen. This approach is available for the study of the hardness testing. Second, a new data processing method for experimental results is developed. Many circles printed in the specimen are used to measure the strain ---- the scribed circle method. In this report the method to detect the circles by using an image-sensing camera is found out, which scans the inner side of each circle. This method can be easily extended to the applied field of this kind of strain measurement. Third, the qualitative deformation of the specimen under indentation with punch is found out experimentally. The contours of the equivalent plastic strain are presented by using the scribed circle method, and the domains near the both ends of the contact area are strained in high level. Also the effects with and without grease between the punch and the specimen can not be found out clearly in the deformation in the specimen. The above analytical processing methods can be applied for deformation and failure of the material in the plastic working.