直撞式霍普金森压杆二次加载技术  

Direct-impact double-loading Hopkinson bar technique

作　　者：钟东海 郭鑫 熊雪梅 郑宇轩[1] 宋力[1] ZHONG Donghai;GUO Xin;XIONG Xuemei;ZHENG Yuxuan;SONG Li(Key Laboratory of Impact and Safety Engineering,Ministry of Education,Ningbo University,Ningbo 315211,Zhejiang,China)

机构地区：[1]宁波大学冲击与安全工程教育部重点实验室,浙江宁波315211

出　　处：《爆炸与冲击》2023年第4期78-86,共9页Explosion and Shock Waves

基　　金：国家自然科学基金面上项目(12272193,12072169,11972203)。

摘　　要：利用传统分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)实验技术来实现试件在较低应变率下的大变形时,需要使用超长的压杆系统,杆件的加工和实验空间限制了该技术的推广应用。鉴于此,提出一种直撞式霍普金森压杆二次加载实验技术,利用透射杆中的应力波在其末端的准刚性壁反射实现对试件的二次加载,并分析了准刚性质量块尺寸对二次加载的影响规律;采用二点波分离方法对叠加的应力波进行了有效分离和计算,在总长4 m的压杆系统中实现了1.2 ms的长历时加载,并可以准确获得试件的加载应变率曲线和应力应变关系。建立了直撞式霍普金森压杆二次加载有限元模型,数值仿真结果表明,该实验技术能有效地实现试件的二次加载,与超长SHPB系统获得的仿真结果相比较,两者的试件应力应变关系完全一致。利用该技术对1100铝合金材料进行动态压缩实验,实现了其在10^(2) s^(−1)量级应变率下的大变形动态力学性能测试。When the conventional split Hopkinson pressure bar(SHPB)experimental method is used to realize large deformation of the specimen at a low strain rate,it is often necessary to employ an ultra-long compression bar system.However,the high cost of machining long bars and occupying large laboratory space limits the application and generalization of this technique.In this paper,a direct impact Hopkinson pressure bar double loading experimental technique is proposed.The stress wave in the transmission bar is reflected by the quasi-rigid wall at the end of the transmission bar to realize the double loading of the specimen.The influence of the size of the quasi-rigid mass on the double loading is further analyzed.The two-point wave separation method is used to separate and calculate the superimposed stress wave effectively,and the long duration loading of 1.2 ms is realized in the pressure bar system with a total length of 4 m,and the strain rate curve and stress-strain relationship of the specimen are obtained accurately.The finite element model of both direct-impact double loading and ultra-long Hopkinson bars are established.Numerical results indicate that this experimental technique can effectively achieve double loading of the specimen.Comparing the simulation results of direct-impact double loading Hopkinson bar with those of ultra-long Hopkinson bars,it is evident that the stress-strain relationships obtained by the two experimental devices are completely consistent.For direct-impact double loading Hopkinson bar,the stress-strain relationship calculated by the two-point wave separation technique is the same as that obtained by direct extraction method.Then,an experimental device of direct impact double-loading Hopkinson pressure bar has been set up,including a strike bar,a transmission bar and a rigid block.In addition,the dynamic compression experiment of aluminum alloy was carried out using this device,and the large deformation dynamic mechanical properties of aluminum alloy were tested under the strain rate of 1

关 键 词：SHPB 二次加载 波反演技术 中应变率加载 大变形 

分 类 号：O347.4[理学—固体力学]