结构损伤识别中部分相关噪声模型

详细地讨论了噪声的来源和产生的物理机制,分析了经典不相关噪声模型的物理意义和适用范围,将测试噪声分为与信号大小无关的测试系统基础噪声和与测试信号幅值和相位有关的环境噪声两部分,提出与结构试验实际环境符合的部分相关噪声模型.计算比较了部分相关噪声模型和传统噪声模型下仿真测试信号的信噪比和方差比,并比较了其对结构振型的识别精度和损伤识别定位的影响.结果表明,所提出的部分相关噪声模型较为符合工程测试实际,而传统噪声模型未能有效模拟系统和环境噪声.

Partial correlation noise model for structural damage identification

The sources and physical mechanism of various noises are discussed in detail and the physical significance and application scope of traditional uncorrelated noise model are analyzed. Based on these discussions, various noises are further classified into two groups: system fundamental noise and environmental noise. The first group of noises is independent of the measured signal and the second is closely correlated to the amplitude and phase of the measured signal through interacting with environmental interferences. A partial correlation noise model is thus proposed to account for the uncorrelated system fundamental noise and correlated environmental noise. Variation ratios and signal to noise ratios of the simulated test signals with traditional uncorrelated noise model and the partial correlation noise model developed are compared. Furthermore, the influences of both models on the identification of mode shapes and damages of a beam are analyzed. It is found that the proposed partial correlation noise model agrees well with engineering practice, while the traditional uncorrelated noise model could not effectively simulate the system and environmental noises.