轴向冲击下弹性杆中轴向静载对入射波的影响

针对动静组合加载试验装置和一维应力波理论的研究现状，研究了轴向静载荷的大小对弹性杆上入射波的影响。首先，以动静组合加载试验装置中具有轴压的入射杆和轴压端帽为研究对象，利用一维应力波理论，研究冲头以一定速度撞击轴压端帽时，入射杆上的入射波与轴压的关系。进而，通过分析自由弹性杆与具有一定轴压的弹性杆共轴撞击，研究轴向静载荷的大小对入射波峰值应力和波长的影响。最后，利用动静组合加载试验装置和激光测速仪进行试验研究，验证理论分析结果的正确性。结果表明：弹性杆中轴向静载荷的大小对其上入射波影响较大，轴向静载荷与入射波峰值应力具有线性关系；轴压越大，入射波峰值应力越小，入射波波长越小。加载应力波上升沿时间越长，轴向静载荷对入射波波长影响越大。

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.