Pulsed holographic microscopy is applied to take photographs of rapidly bifurcating cracks in PMMA plate specimens. The cracks are of the opening mode and propagate at a speed more than 600 m/s. The photographs are simultaneously taken on the both side of the specimens about 10 μs after bifurcation. The photographs show that, in many cases, the bifurcated crack's shape on one side of a specimen is apparently different from that on the other side of the specimen. Even in the case of cracks that have similar shapes on the both sides of specimens, the crack shapes are different near the bifurcation points on the both sides of the specimens. These facts indicate that the rapid crack bifurcation in PMMA is three dimensional phenomenon. Also shown is the example that two crack branches have different crack opening displacements. It means that the bifurcation of the crack was asymmetric with respect to the line along the mother crack.
|ジャーナル||Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|出版ステータス||Published - 2002 11月|
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