Image analysis of the unstable crack growth under compresive loading condition with ultra-high-speed video camera

对准静态加载条件下裂纹的不稳定扩展进行了实验和数值研究。利用1Mfps的超高速摄像机成功地拍摄到了裂纹扩展过程和扩展裂纹尖端应力分布的图像，并利用光弹技术对图像进行了可视化。其次，本文提出了一种数值模拟裂纹失稳扩展的方法。仿真结果与实验结果吻合较好，表明该算法具有足够的精度。

Unstable crack growth under the quasi-static loading condition is studied experimentally and numerically. Images of the crack growth and the stress distribution around the growing crack tip, which is visualized by using photo-elastic technique, are successfully captured by the ultra-high-speed video camera with the frame rate of 1Mfps. Next, numerical algorithm to simulate the unstable crack growth is proposed in this work. The simulation result shows a good agreement with the experimental result, and it is shown that the proposed algorithm has the sufficient accuracy.