【摘要】 为了分析CCCD-SHPB动态断裂试验系统试验结果的有效性,采用3维动态有限元方法分析了试件几何尺寸和入射杆、透射杆材料对实验结果的影响。分析结果表明,试件直径对CCCD-SHPB动态断裂试验系统的试验结果有较大影响,而入射杆和透射杆的波阻抗与试件的波阻抗是否匹配会影响试验结果的精度,但在一定尺寸范围内,试件厚度对试验结果影响较小。进一步计算结果表明,在动态加载的初期阶段,由于试件两边载荷不平衡,导致CCCD-SHPB动态断裂试验系统中存在与试件尺寸相关的特征时间ΔT,且ΔT近似等于应力波在试件中来回往返两次的时间;动态断裂试验时,试件从加载至断裂的时间应大于特征时间ΔT,否则试验结果不可靠。更多还原

【Abstract】 In order to analyze the validity of testing results for CCCD-SHPB dynamic fracture test system,3-D dynamic finite element method was employed to investigate the effects of specimen’s geometric size and incident/transmitted bar’s material on the testing results.The analysis confirms that the specimen diameter has a significant effect on the testing result of CCCD-SHPB(central cracked circular disk-split Hopkinson pressure bar)dynamic fracture test system,and whether or not matching of the incident/transmitted bar’s impedence with the specimen’s impedence has an effect on the precision of the testing result,but the specimen thickness,to some extent,has less effect on the testing result.Due to the unbalance of loads on two sides of specimen at the early stages of dynamic loading,a characteristic time ΔT,which is dependent on specimen size,is introduced in the present paper.Its value is approximately equal to the time of which stress wave travels back and forth in the specimen for two times.It is necessary that the time of which specimen is loaded till fracture must be greater than ΔT when the dynamic fracture test is conducted.更多还原