FFT和MEM在冲击回波法识别混凝土缺陷尺寸中的对比研究  

Comparative Study on FFT and MEM in IdentifyingConcrete Defect Size by Impact Echo Method

作　　者：杨海林 YANG Hailin(Tangshan Polytechnic College,Tangshan 063299,China)

机构地区：[1]唐山工业职业技术学院,河北唐山063299

出　　处：《工业技术与职业教育》2024年第1期12-17,共6页Industrial Technology and Vocational Education

基　　金：2023—2024年度唐山工业职业技术学院院级课题“冲击回波法定量识别预应力孔道压浆缺陷尺寸的应用研究”(课题编号:YJKT202306),主持人杨海林。

摘　　要：针对冲击回波法识别混凝土缺陷尺寸的两种信号分析方法,通过理论分析与现场模型试验,研究了FFT(快速傅里叶变换)和MEM(最大熵法)在冲击回波信号处理中的应用,结果表明:FFT算法简单快速,但分析过程添加的窗函数会导致频谱泄露和分辨率降低;MEM算法可以对已知数据外的信号进行合理估计,具有较高的分辨率,更加符合实际工程的要求;频谱图和卓越周期图可以携带缺陷信息,缺陷在FFT计算结果中体现为峰值提前,在MEM计算结果中体现为峰值延后;等值线图可以更加直观地识别缺陷位置,MEM的计算结果比FFT计算结果精度更高。Aiming at two signal analysis methods for identifying concrete defect size by impact echo method,the application of FFT and MEM in impact echo signal processing was studied through theoretical analysis and field model test.The results show that the FFT algorithm is simple and fast,but adding window functions during the analysis process can lead to spectrum leakage and reduced resolution;The MEM algorithm can reasonably estimate signals outside the known data,and it has higher resolution,which is more in line with the requirements of practical engineering;The spectrum and predominant period can carry defect information,which is reflected as peak advance in FFT calculation results and peak delay in MEM calculation results;The contour map can more intuitively identify the presence of defects,and the calculation results of MEM have higher accuracy than those of FFT.

关 键 词：FFT MEM 冲击回波 缺陷尺寸 卓越周期 等值线图 

分 类 号：TU375[建筑科学—结构工程]