基于双树复小波降噪和Katz分形维迹线融合的板类结构损伤检测

发布时间：2018-08-29 13:24

【摘要】：目前基于振动响应的板类结构损伤检测技术存在着噪声免疫力弱、对轻微损伤难以识别等困难。对此,提出一种对板振型进行双树复小波变换(DT-CWT)降噪和仿射变换预处理的Katz分形维迹线扫描融合的板结构损伤检测方法。该方法首先利用DT-CWT对原始实测板结构的振型信号进行降噪;然后将降噪后的振型沿板纵、横向离散分解为振型曲线;将分解后的振型曲线进行仿射变换,得到拉伸后的线型面图;对变换后的线型面图分别进行Katz分形维迹线扫描,得到沿板纵向和横向的分形维迹线曲面图,将二者取均值得到融合后的分形维迹线曲面图;此融合后的曲面图中的凸起预示了损伤的发生,凸起的位置、形状和尺寸反应了损伤所在的位置、形状和尺寸。通过两个模型试验证明了该方法对板结构损伤识别的有效性;对比分析说明了对振型进行DT-CWT降噪和仿射变换预处理的重要性。
[Abstract]:At present, it is difficult to detect the damage of plate structure based on vibration response, such as weak noise immunity and difficulty in identifying slight damage. In this paper, a new damage detection method for plate structures based on Katz fractal trace scanning fusion with dual tree complex wavelet transform (DT-CWT) and affine transform preprocessing is proposed. The method firstly uses DT-CWT to de-noise the vibration signal of the original measured plate structure, then decomposes the de-noised mode into the mode curve along the longitudinal and transverse direction of the plate, and affine the decomposed mode curve. The lines and surfaces are scanned by the Katz fractal trace line, and the fractal dimension trace and surface images along the longitudinal and transverse direction of the plate are obtained, and the fused fractal dimension trace and surface images are obtained by taking the mean values of the two images. The protrusions in the fused surface map predict the occurrence of the damage, and the position, shape and size of the protuberance reflect the location, shape and size of the damage. The effectiveness of the method is proved by two model tests, and the importance of DT-CWT noise reduction and affine transform preprocessing for vibration modes is compared and analyzed.
【作者单位】：山东农业大学水利土木工程学院;河海大学力学与材料学院;
【基金】：国家自然科学基金(51508156) 中国博士后科学基金(2014M560386) 山东省自然科学基金(ZR2014EL034)
【分类号】：O346.5

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