EFFECT OF AXIAL STATIC STRESS OF ELASTIC BAR ON INCIDENT STRESS WAVE UNDER AXIAL IMPACT LOADING

Aiming at a research status of a split Hopkinson pressure bar (SHPB) device with static and dynamic loadings and one-dimensional stress wave theory, the effect of static axial stress on the incident stress wave of an elastic bar were studied. Firstly, based on one-dimensional stress wave theory, the relationship between the incident wave and static axial stress in an incident bar was investigated when a striker impacts against a thin baffle screen with a constant velocity. And then, the effect of static axial stress on the peak stress and wavelength of incident stress wave was researched by analyzing the coaxial impact of a free elastic bar and an axial pre-stressed bar. Finally, experiments were carried out on an SHPB device with static and dynamic loadings to verify the theoretical analysis results. The results show that the static axial stress in an elastic bar has a great effect on incident stress wave, the peak stress of incident stress wave reduce linearly with the increase of static axial stress. The bigger static axial stress is, the smaller wavelength of incident stress wave is. The longer rising time of loading stress wave is, the greater the effect of static axial stress on incident stress wavelength is.