動光弾性被膜と超高速カメラによる衝撃曲げ挙動の解析

抄録

The dynamic stress distribution, crack initiation and propagation at the bottom of the notch under impulsive bending load were investigated by using the dynamic photoelastic method repeatedly and the velocity gage method. Photoelastic coatings were bonded to the resin mortar plates and aluminum alloy specimens, and these specimens were loaded dynamically by the falling impact indentor. Isochromatic patterns in the coating resin were satisfactorily taken at various stage of impact of the test pieces by the ultra high-speed camera, that is the image converter camera IMACON-790. The measurement of fracture speed made in this way was compared with an alternate technique in which an array of electrically conducting paint stripes was arranged on the other surface so as to signal an open circuit on crack arrival. Finally, it is shown that the photoelastic coatings are very much useful to enhance surfacecrack visualization subsequent to impact, and that the maximum propagating velocity of the crack in the resin mortar is about 900m/s.