高速進展き裂の分岐時におけるき裂開口変位とエネルギー解放率の測定
2001 年 67 巻 664 号 p. 2010-2017
詳細
2001 年 67 巻 664 号 p. 2010-2017
High speed holographic microscopy is applied to take three successive photographs of fast propagating cracks at the moment of bifurcation. The cracks are propagated in PMMA plate specimens at a speed of about 660m/s. From the photographs, crack opening displacement (COD) is measured along the cracks as a function of distance γ from the crack tips. The measurement results show that the CODS are proportional to √(γ) before bifurcation. After bifureation, the CODS of mother cracks are proportional to √(γ), however, those of bifurcated cracks are not always proportional to √(γ). The energy release rate is obtained from the COD data, and is found to be continuous across the bifurcation point. The continuity of the energy release rate is explained through the fact that the bifurcated cracks appear as three dimensional cracks, not as through cracks.
