Investigation for prolongation of incident wave in impact tensile test

Abstract

In the Split-Hopkinson bar method, the duration of stress wave depends on the length of the striker. For the extension of the duration, therefore, the test equipment becomes huge because of long striker. In the previous study, it was attempted that the incident wave was prolonged by attaching an extended bar to the flange and connecting two stress waves. However, this device could not control the disturbance of stress wave due to the flange and the connection of the two tensile waves was not necessarily successful. Thus, in this research, analytical study was conducted on the connection method of two tensile waves by using a stepped bar model with the same mechanical impedance instead of the flange part. It was found that the disturbance generated in the center of the connected stress wave is smaller in our stepped bar model than in the flange model. It was also found that the cause of the disturbance occurring in the center of the connected stress wave is the vibration on the wave front of incident compression pulse propagating in the extended bar.