夹心杆系统中一维弹塑性波演化精细分析(Ⅰ):典型加载波的透反射  

Meticulous analysis of one-dimensional elastic-plastic wave evolution in sandwich bar system(partⅠ):transmitted and reflected waves for typical loading waves

作　　者：高光发[1] GAO Guangfa(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094

出　　处：《爆炸与冲击》2024年第8期108-119,共12页Explosion and Shock Waves

基　　金：国家自然科学基金(12172179,11772160,11472008)。

摘　　要：准确地剖析反射波与透射波的形成过程与影响机理是SHPB(split Hopkinson pressure bar)精细化试验设计与精准数据处理的核心前提之一。针对夹心杆系统,分析矩形、梯形与半正弦三种典型入射波加载阶段系统中一维弹塑性波的传播与演化,定量研究试件中弹塑性波的传播、两个界面上弹塑性的透反射及其系列透反射波的相互作用影响。结果表明:首先,弹塑性波特别是应力波在弹塑性交界面上的透反射中占主要地位,纯弹性波的透反射与传播反而影响较小;其次,当入射波加载区间有一定的宽度时,杆2中弹性波在两个界面上的多次透反射对反射波造成衰减的同时对透射波进一步强化,这种衰减使得半正弦波对应的反射波峰值并不是在0.5个无量纲时间时,而是有所提前;第三,与传统SHPB分析中弹性波在界面上透反射的初步规律不同,无论是矩形波、梯形波还是半正弦波入射时,试件材料的杨氏模量与密度改变虽然明显影响其弹性波的阻抗比,但对透反射波波形及其峰值强度影响并不明显。研究结果可为SHPB的精细化设计与数据的精准分析提供科学依据。The reflected and transmitted waves in split Hopkinson pressure bar(SHPB)tests provide crucial information for obtaining the stress-strain relationship of materials.Accurately analyzing the formation process and influencing mechanisms of the reflected and incident waves is a key prerequisite for precise experimental design and accurate data processing.In this paper,the propagation and evolution of one-dimensional elastic-plastic waves in the loading stages of the SHPB test are presented particularly for a sandwich bar system consisting of the incident wave,specimen,and transmitted bar.Based on the theory of elastic-plastic incremental waves and numerical simulation calculations,the propagation of elastic-plastic waves in the specimen,the transmission and reflection of elastic-plastic waves at the two interfaces,and the interaction of the resulting series of transmitted and reflected waves are quantitatively investigated.The research findings are as follows.Firstly,although the design principle of the SHPB apparatus is based on linear elastic wave theory,the elastic-plastic waves,especially the stress waves,have a major influence on the transmission and reflection at the elastic-plastic interface,while the transmission and propagation of purely elastic waves have a relatively minor effect.Secondly,when the loading interval of the incident wave has a certain width,the multiple transmission and reflection of elastic waves at the two interfaces in bar 2 attenuate the reflected wave while further strengthening the transmitted wave.This attenuation causes the peak of the reflected wave for the half-sine wave to occur earlier than at 0.5 nondimensional time.Thirdly,in contrary to the preliminary laws of elastic wave transmission and reflection at interfaces in traditional SHPB analysis,variations in the Young’s modulus and density of the specimen material have little effect on the waveform and peak intensity of the transmitted wave,regardless of whether the incident wave is rectangular,trapezoidal,or half-sine.This in

关 键 词：SHPB 弹塑性波透反射 反射波 透射波 广义波阻抗 

分 类 号：O347.4[理学—固体力学]