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高速進展き裂前縁のホログラフィ撮影 Pulsed Holography for Photographing Fast Propagating Crack Fronts 鈴木, 新一 吉山, 育伸 SUZUKI, Shinichi YOSHIYAMA, Ikunobu Fracture Measurement Optical_Engineering Holography Crack_Front Dynamic_Fracture Three-dimensional_Stress_Field Fracture Measurement Optical_Engineering Holography Crack_Front Dynamic_Fracture Three-dimensional_Stress_Field Pulsed holography is applied to take an instantaneous photograph of a crack front propagating through a PMMA plate specimen at a speed of several hundred m/s. The cracks are in the opening mode and not interacting with any stress waves. A pulsed holographic optical system records and reconstructs a crack front observed through a side boundary of a specimen, and the reconstructed image is photographed. A method is developed to decrease an aberration introduced by inhomogeneity of refractive index in PMMA, where the inhomogenity results from manufacturing process of the PMMA. Also discussed are effects of changes of specimen thickness and refractive index in the strong stress field near a crack tip. From an obtained photograph one can know the shape of a crack front, which is not always symmetric. One can moreover measure the two angles between the crack front and the two specimen surfaces. The angles are important quantities to understand the three-dimensional structure of the stress field around the crack tip. The measured angles are similar to the numerical results given by Bazant and Estenssoro. ・rights：日本機械学会 ・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである ・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002373097/ 一般社団法人日本機械学会 1990-05-25 jpn journal article VoR https://repo.lib.tut.ac.jp/records/1239 http://ci.nii.ac.jp/naid/110002373097/ CiNii 03875008 日本機械学會論文集. A編 Transactions of the Japan Society of Mechanical Engineers. A 56 525 1107 1115 https://repo.lib.tut.ac.jp/record/1239/files/n03875008-0056-1107.pdf application/pdf 681.3 kB 2013-07-22