@article{oai:repo.lib.tut.ac.jp:00001231, author = {鈴木, 新一 and 布施, 壽則 and 中島, 卓郎 and 草鹿, 履一郎 and SUZUKI, Shinichi and FUSE, Hisanori and NAKAJIMA, Takurou and KUSAKA, Riichiro}, issue = {514}, journal = {日本機械学會論文集. A編, Transactions of the Japan Society of Mechanical Engineers. A}, month = {Jun}, note = {Pulsed holographic microscopy is applied to kake instantaneous microscopic photographs of the neighborhoods of crack tips propagating through AISI 4340 steel specimens at a speed of about 300m/ s. We use a holographic optical system with a Q-switched ruby laser which records scattered light from crack edges and from specimen surfaces as object light. A method for brteaking the specimens is devised to synchronize the laser oscillation with the generation and propagation of a crack. Two microscopic photographs are obtained. From each photograph, the crack opening displacement (COD) is measured along the crack within 10 mm of the crack tip. The COD is of the order of ten to one hundred micrometers, and is proposional to the square root of the distance from the crack tip. Dynamic fracture toughness K_ is calculated through the formula of COD in the singular stress field of a propagating crack., ・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/110002373771/}, pages = {1311--1318}, title = {パルスホログラフィー顕微鏡法を用いた4340鋼中高速進展き裂先端部の撮影}, volume = {55}, year = {1989} }