破面形態判別のための破面特徴量抽出に関する研究

The fractography is one of the useful technique for finding the cause of breakage in the engineering
par ts. However, it is not easy to find an appropriate point on the fracture surface, and also the
distinction of fracture surface morphology, such as dimple, river-pattern, striation and so on, needs
highly skilled technique. To assist unskilled engineers, there are many studies for quantitative
analysis of fracture surface morphology by means of Fractal dimension measurement. It is very
interesting that fracture surface possesses fractal structure, but it is still difficult to distinguish
the fracture surface morphology by using fractal dimensions measurement. On the other hand,
Recurrence plots introduced by Eckmann et al. provide a way to visualize the periodic nature of events such as fracture surface’s characteristic feature. Therefore, by applying the image recognition technique to Recurrence plots obtained from fracture surface, it is expected to see the fractographical feature extraction for distinguishing fracture surface morphology.
In this study, in order to recognize the Intergranular fracture on fatigue-fractured spring specimen in a salt water environment, the image recognition technique is applied to Recurrence plots obtained from fracture surface. Since we obtained appropriate judgements for intergranular fracture, it is found that Recurrence plots and image recognition technique could be useful for a computer aided fractographical new technique.

Fracture surface, Fractography, Recurrence plots, Intergranular fracture, Striation, Dimple