基桩超声波检测频域分析的应用研究

发布时间：2018-01-29 04:29

本文关键词： 频域分析基桩检测频域特征超声波震源仿真分析　出处：《华中科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：目前基桩超声波检测中，主要对接收信号进行时域分析，以声时、首波波幅、主频、波形来综合判断桩身完整性，然而对接收信号的频谱信息的研究和应用很少，国内外的一些研究者主要在试验的基础上分析超声波频域特征，由于测试条件，测试方法不同，所得结果有局限性，因此超声波频域分析在基桩检测中的应用尚缺乏系统的理论分析和数值仿真计算。本文应用ANSYS/LS-DYNA有限元动力分析软件对基桩超声波频域分析进行仿真计算，重点分析超声波频域的特征。论文首先探讨超声波震源的选择问题，用MATLAB软件仿真分析超声波震源加不同窗函数处理后的频谱特征，分析不同窗函数的特点，选择合理的窗函数，并研究减少频谱泄露、提高频域分辨率的方法；接着，用LS-DYNA软件模拟超声波在桩体内的传播，，分析超声波在桩身混凝土中的传播特点，通过波速的计算验证LS-DYNA计算桩波动问题的正确性；在此基础上，通过LS-DYNA仿真计算对不同截面桩接收信号进行频域分析，分析频域特征，并对主要的频谱信息进行解释，讨论截面形状、测试方法、不同测点、不同测距、缺陷对频域的影响，总结相应的规律；然后，对工程实测时域信号频谱分析，验证仿真成果的正确性，并提出实际超声波检测的相关建议。本文就超声波频域分析在基桩检测中的应用作了较为深入的研究分析，研究成果具有一定的应用和推广价值。
[Abstract]:At present, the ultrasonic pile testing, mainly on the receiving signal of time domain analysis, the sound, the first wave amplitude, frequency, waveform judgement of pile integrity, but the research and application of spectrum information of the received signal is very few, some researchers at home and abroad is the analysis of the frequency characteristics of ultrasonic wave on the basis of the experiment, because test conditions, different test methods, the results have limitations, so the ultrasonic spectrum analysis application in pile foundation inspection is still lack of theoretical analysis and numerical simulation calculation system. This paper using ANSYS/LS-DYNA finite element dynamic analysis software of pile foundation ultrasonic spectrum analysis of the simulation, analysis of key features of ultrasonic spectrum.
The paper first discusses the selection of ultrasonic source, spectrum analysis of ultrasonic source with different window function after treatment by MATLAB software simulation, analysis of the characteristics of different window functions, reasonable choice of window function, and reduce the spectrum leakage, improve the frequency resolution of the method; then, simulation of the ultrasonic wave in the pile body by LS-DYNA software analysis, the ultrasonic transmission characteristics in the pile of concrete pile, the correctness of the fluctuation velocity through the calculation and verification of LS-DYNA calculation; on this basis, through the LS-DYNA simulation calculation of different section pile receiving signal frequency domain analysis, frequency domain analysis of spectrum characteristics, information mainly explained the discussion, section shape, test method. The different measuring points, different distance, influence of defects on the frequency domain, summarizes the corresponding rules; then, analysis of the measured time domain signal spectrum, simulation The results are correct and some suggestions for actual ultrasonic testing are put forward.
This paper makes a thorough research and Analysis on the application of ultrasonic frequency domain analysis in foundation pile detection, and the research results have certain application and popularization value.

【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.16

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