摘要
为了探究混凝土结构在瞬时冲击荷载作用下的响应特征以及应力波在混凝土介质中的传播规律和影响因素,进一步完善冲击回波法检测理论和提高混凝土缺陷检测与识别精度,基于ADINA有限元分析软件,设计构建了一系列有缺陷和无缺陷的混凝土板结构有限元模型,运用动力有限元分析理论,对混凝土结构冲击回波响应特征以及弹性应力波传播的动力学特征进行数值仿真分析。结果显示:混凝土板内有缺陷存在时,板厚对应频率均向低频漂移,且方形空洞比圆形空洞引起的漂移量稍大;当缺陷埋深超过缺陷横向尺寸3倍以上时,分析结果的偏差会陡然增大;对埋深小于10 cm的浅表层缺陷,其偏差值较大。结果表明,有限元仿真分析直观地展现了应力波在混凝土介质中的动态传播过程以及波场与缺陷体相互作用的规律,仿真分析结果与应力波传播基本理论及物理模型试验结果基本一致,验证了本有限元模型的合理性以及数值仿真分析方法的适用性和可行性。
In order to explore the response characteristics of concrete structures under instantaneous impact load as well as the propagation law and influencing factors of stress wave in concrete medium for further improving the detection theory of impact-echo method and enhancing the detection and identification accuracies of concrete defect,a series of finite element models of concrete slab structures with and without defects are designed and established through the ADINA finite element analysis software,and then the numerical simulation analyses on the impact echo response characteristics and the dynamics characteristics of the elastic stress wave propagation of the concrete structures are carried out herein by means of the relevant dynamic finite element analysis theory.The study result shows that all the frequencies corresponding to slab thicknesses are to drift to the low-frequencies when defects are there in concrete slab,meanwhile,the frequency drift caused by square void is slightly larger than that caused by circular one.When the buried depth of defect is three times over the transverse dimension of the defect,the deviation of the analysis result is to be sharply increased,while its deviation value is relatively larger for the shallow defect with the buried depth less than 10cm.The result indicates that the dynamic propagation process of the stress wave in concrete medium and the law of the interaction between the wave field and the defect body are intuitively displayed by the finite element simulative analysis,while the simulative analysis result is consistent with both the basic theory of stress wave propagation and the result of the relevant model experiment,thus verifies the reasonability of this finite element model as well as the applicability and feasibility of the numerical simulation analysis method.
作者
张景奎
郑继
罗居刚
刘长顺
许军才
ZHANG Jingkui;ZHENG Ji;LUO Jugang;LIU Changshun;XU Juncai(Water Resources Research Institute of Anhui Province and Huaihe River Commission,MWR.,Bengbu 230000,Anhui,China)
出处
《水利水电技术》
北大核心
2020年第6期164-171,共8页
Water Resources and Hydropower Engineering
基金
安徽省水利厅科研及技术咨询项目(slkj2018-05)。
关键词
混凝土
内部缺陷
冲击回波法
有限元
仿真分析
concrete
internal defects
impact-echo method
finite element simulative analysis
