High strain rate fracture and impact mechanics

According to previous studies, the dynamic yield strength increases but the dynamic fracture toughness decreases with increasing loading rate. The dynamic stress concentration behavior of a strip with a shoulder fillet and the stress distribution in a bar subjected to an impact force are investigated. In these results, size dependence of the impact stress caused by the superposition of stress waves was observed. The impact fatigue life and impact fracture toughness also exhibit size dependence. In addition, dis-advantageous aspects of conventional evaluation method for the impact strength of materials and a new simple practical method are described.