基于盲源分离的钢筋混凝土梁非线性振动特性分析

将盲源分离技术应用于结构非线性振动特性分析,在小波软阈值去噪的基础上,用二阶统计量盲辨识(SOBI)算法从结构的振动信号中分离出第一阶振动分量,然后利用Hilbert变换得到频率与振幅的关系。在数值仿真算例的基础上,采用钢筋混凝土简支梁和预应力箱梁的试验数据,验证了在分析结构非线性振动特性时,盲源分离技术抗噪性好,比短时傅氏变换更易操作。结果表明:在较小损伤的情况下,利用非线性振动特性识别结构损伤程度,有时比由基于线性振动的模态识别得到的结构频率改变的方式更可靠。

ANALYSIS OF NON-LINEAR VIBRATION OF RC BEAMS BY USING BLIND SOURCE SEPARATION

Blind source separation was used to analyze non-linear vibration of RC beams.The algorithm called second-order blind identification was applied to the structural vibration signals de-noised by wavelet soft-thresholding to acquire the first order vibrational component,which was then processed by Hilbert transformation to get the frequency-amplitude curve.Based on the verification by finite element simulations,the recorded vibration signals of a RC simple beam and a prestressed simple box-beam were analyzed by the above procedures.The results show that blind source separation has good ability of anti-noise and is better than short time Fourier transformation regarding ease of implementation.In addition,the damage identification by non-linear vibration analysis is reliable than that by frequency change obtained by traditional modal analysis based on linear vibration.