SHTB的拉伸冲击波谱加载方法研究

Tensile impact wave spectrum loading method for SHTB

为了理解动态变形和塑性流动过程中,加载历史和应变率变化对材料性能的影响,基于直接拉伸式Hopkinson杆原理,使用不同几何形状的反射杆代替凸缘法兰,在加载杆中连续产生多个不同幅值的加载冲击波,使材料在动态变形的过程中应变率阶跃变化。结果表明:(1)该方法可以将加载波的脉宽延长3倍以上,有利于进行低应变率、大变形的材料试验;(2)加载应力波的幅值阶梯变化,使试样在加载过程中应变率发生跳跃变化;(3)通过控制反射杆的长度可以有效控制加载脉冲的间隔,将材料的应变率效应和温度效应解耦,用于揭示不同脉冲幅值作用下试样变形损伤机制。试验证明,基于SHTB原理的拉伸波谱的加载方法可以快速、精准、稳定地实现对试样的连续多次动态加载。

Here,to understand effects of loading history and strain rate change on material properties in process of dynamic deformation and plastic flows,based on the principle of direct tensile Hopkinson rod,reflective rods with different geometric shapes were used to replace flange,and multiple loading impact waves with different amplitudes were continuously generated in loading rod to make strain rate of material have step changes in process of dynamic deformation.The results showed that(1)the proposed method can prolong the pulse width of loading wave by more than 3 times to be conducive to material tests with low strain rate and large deformation;(2)amplitude step change of loading stress wave makes the specimen's strain rate jump during loading;(3)controlling length of reflecting rod can effectively control spacing of loading pulses to decouple material's strain rate effect and temperature effect,and reveal deformation and damage mechanism of specimens under action of different pulse amplitudes.Tests showed that the loading method of tensile wave spectrum based on SHTB principle can quickly,accurately and stably realize continuous and multi-dynamic loading of specimens.