Measurement of Stress-strain Relation by Means of Instrumented Charpy Impact Bending

点击翻译按钮获取中文摘要

Some experimental studies on the measurement of stress-strain relations by means of Charpy impact bending were carried out and the practical application of them were discussed. Stress-strain relations obtained are based on the simple plastic bending theory of a beam specimen under instrumented Charpy impact bending, where the statics is supposed in determining the impact bending moment from the impact load estimated by impact response function of convolutional integral and the bending strain is measured by a strain gage cemented to the back side of impact point. The present results using various specimens were compared with those by impact compression of Hopkinson bar type. As a result, it was found that the present method was available except for the case of small strain or low strength materials, though more or less fluctuations were seen in stress-strain relation obtained. Furthermore dynamic stress-strain relations of heat treated steel alloys with high hardness were obtained by the present method. So the strain rate and the hardness dependency of yield or fracture strengths of them was studied. According to the result the strength becomes maximum at Vickers hardness HV600-700 and it is not so affected by strain rate.