抄録
Here under is presented, based on the elementary theory of one-dimensional stress wave propagation, a numerical method to draft the stress-strain curves for the materials under impact tensile load, by making use of a bar and a pipe of mild steel. The materials used in the present experiment are 0.01% carbon steel and 18-8 stainless steel.
The main results obtained in the range of strain rate (50∼300)sec-1 are as follows.
In the case of 0.01% carbon steel, the yield strength increases with the strain rate. The ratio of dynamic stress to static one corresponding to the strain 2% is (2.3∼3.4) under the strain rate (103∼260)sec-1.
In the case of 18-8 stainless steel, treated in solution but little of dependence of the strain rate on the stress-strain relation has been observed. In the case of 18-8 stainless steel as it was received, however, the stress is influenced more or less by the strain rate, and the larger the strain rate, the higher the stress. The ratios of dynamic stress to the static stress corresponding to the strain 2% for the former case and for the latter are 2.0 and 1.4 respectively, so the dynamic stress is higher than the static in both the cases.
