摘要
为提高声发射技术在混凝土结构损伤检测中的准确度,针对弹性波在混凝土介质中传播出现的频漂现象,采用有限元数值模拟和试验研究了混凝土梁结构中弹性波传播的频漂特性,基于Hilbert-Huang变换中的Hilbert边际谱,分析了仿真和试验结果中不同频率段的频率衰减特性,取得了较好的一致性,即频漂具有自相似性和整体性两大特点,其中自相似性体现为不同宽度频率段的频率成分均近似呈指数型衰减,且频率段频率越高,衰减系数越大;整体性则体现为主频随传播距离的增加快速向低频移动。
To improve the accuracy of damage identification of the acoustic emission technology （AET） in the detection of concrete structures, and aiming at the frequency drift phenomenon generated by the wave propagation in concrete, the finite element numerical simulation and experiment are used to investigate the elastic wave propagation characteristics in concrete beams. The accumulation property of Hilbert marginal spectrum is applied to analyze both the simulation sig- nals and the experimental signals by different frequency bands. The results show that the experimental results agreed with the simulation results. That is the frequency drift has characteristics of self-similarity and global domain property. The self-similarity meant that the frequency band has a certain width approximate exponential decay, and the higher is the fre- quency, the larger is the attenuation coefficient. The global domain property referred that the dominant frequency moved quickly to the lower frequency with increasing the propagation distance.
出处
《水电能源科学》
北大核心
2013年第1期100-103,共4页
Water Resources and Power
基金
国家高技术研究发展计划(863计划)基金资助项目(2009AA03Z107)
国家自然科学基金资助项目(50875114)
关键词
混凝土梁
弹性波
频漂
Hilbert边际谱
concrete beam
elastic wave
frequency drift
Hilbert marginal spectrum
