Pulsed holographic microscopy is applied to take photographs of a rapidly bifurcating crack in a PMMA plate specimen. The crack is the opening mode and propagates at a speed more than 600 m/s. Two photographs are simultaneously taken on the both sides of the specimen about 15 μs after bifurcation. Crack opening dislacements, CODs, of branch cracks are measured from the photographs on both specimen surfaces. It is found that one of the two branch cracks appears as a surface crack, Also found is that the two branch cracks propagate at the same speed even though one of the two branch cracks is not linked to the mother crack on one side of the specimen. And the CODs of the branch crack that didn't perfectly connect with the mother crack become smaller near the bifurcation point. This fact indicates clearly that the rapid crack bifurcation is three dimensional phenomenon.
|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 - 2004 9|
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