动态压缩下混凝土应变率效应压力与横向效应的影响与校正  

Influence and Revision of Transverse Inertia Effect and Pressure Hardening Effect on Strain-Rate Hardening Effect of Compressive Strength of Concrete

作　　者：高光发[1,2] GAO Guang-fa(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China;State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094 [2]北京理工大学爆炸科学与技术国家重点实验室,北京100081

出　　处：《北京理工大学学报》2020年第2期135-142,149,共9页Transactions of Beijing Institute of Technology

基　　金：国家自然科学基金资助项目(11772160,11472008,11202206,11402266);爆炸科学与技术国家重点实验室基金(KFJJ18-01M);浙江省重中之重学科开放基金项目(xklx1513);中央高校基本科研业务费专项资金(30915118801)。

摘　　要：混凝土在高应变率条件下具有非常明显的应变率强化效应.然而,在动态压缩试验过程中混凝土试件内也必然存在横向惯性效应;而且由于常用的混凝土动态本构关系中应变率效应与静水压影响被假设是解耦的,因此需要对其进行归一化处理.基于试验结果,利用波动力学理论,结合数值计算,对动态压缩试验中试件内的横向惯性效应和静水压效应进行分析和校正,并给出了混凝土材料压缩强度的真实应变率强化规律.研究表明:随着试件径向尺寸与应变率的增加、材料声速和破坏应变的减小,试件的横向惯性效应愈加明显;混凝土试件压缩强度在高应变率区间的应变率强化效应非常明显,对比之下,对试件内横向惯性效应与静水压影响进行校正后的混凝土材料压缩强度的真实应变率强化效应远低于前者;在高应变率区间,混凝土材料由于其内在含孔隙与随机预损伤等结构问题应该存在应变率强化效应,但随着应变率的提高,该强化趋势会减小,直至趋于一个近似恒指.The compressive strength of concrete has a significant strain-rate hardening effect under a high strain-rate loading.However,some problems,such as transverse inertia effect,should be considered even if all conditions in the test process are perfect.And the strain-rate effect and pressure hardening effect are decoupling,so the part of dynamic increase factor which is on account of the increase of pressure must be excluded.Based on previous investigation results,the transverse inertia effect and pressure hardening effect were studied through theoretical analysis and numerical simulation and the true strain-rate effect of concrete was obtained.The study results show that with the increase of the radial size and strain-rate of the specimen,the decrease of sound velocity and the fracture strain of concrete material,the transverse inertia effect is more and more obvious.Compared with the concrete specimen,the strain-rate effect of concrete material is much smaller.Concrete material is a kind of structural material which contains a mass of micro-void and randomly distributed initial damage,so it should be a strain-rate hardening material.

关 键 词：混凝土 应变率效应 动态压缩强度 动态强化因子 横向惯性效应 

分 类 号：O347.3[理学—固体力学]