混凝土材料的SHPB实验技术研究

为提高混凝土材料的SHPB实验结果的精度和可比性,结合混凝土的实验过程,对波导杆的弥散效应、试件内应力应变均匀性和试件的径向惯性效应进行了研究。研究结果表明:一维应力波假定和均匀性假定基本满足,混凝土试件是否有足够时间使应力应变达到均匀,取决于混凝土试件的最大应变值和应变率;实验中采用脉冲整形技术和恒应变率实验技术,并选用三波公式处理实验数据,可以增大混凝土的有效承载时间,减小试件惯性效应对实验结果的影响;当应变率接近或大于104时,需要考虑试件的径向惯性效应。

Experimental Study of SHPB Technique for Concrete Materials

In order to improve the precision and comparability of SHPB testing results of concrete materials,some studies on the SHPB technique for concrete are carried out by combining with the experimental process of concrete in this paper,which include the dispersion effect of waveguide bars,the analysis of stress and strain uniformities in specimen and the radial inertial effect of specimen.The results show that experiments meet the requirements of one-dimensional stress wave assumption and stress/strain uniformity assumption.Whether there is enough time to achieve stress and strain uniformities or not depends on the maximum strain and strain rate of concrete specimen.Pulse shaping technique and constant strain rate test technique are used in the experiments,and the experiment data is processed by using the formula of three waves,which can increase the effective loading time of concrete and reduce the inertia effect of specimen on experiment results.When the strain rate is close to or more than 104,it is necessary to consider the radial inertia effect of specimen.