结构损伤识别中噪声的模拟

Noise simulation in structural damage identification

在有限元仿真的结构振动信号上施加不同水平的噪声,采用随机子空间法,分别从各种噪声水平的信号中提取结构的模态参数。以无噪声信号得到的模态参数为标准值,计算了各信号噪声水平下模态参数的误差,得到了信号噪声水平与模态参数噪声水平的对应关系,给出了模拟模态参数噪声的方式。通过损伤识别算例,考察了识别效果对信号信噪比的要求。

By utilizing the stochastic subspace identification,modal parameters were extracted from simulated vibration signals contaminated by specified levels of noise.With the modal parameters identified from the signal without noise being as the standard,the errors of modal parameters from signals polluted by various levels of noise in relation to the standard were obtained.So the error,i.e,the modal parameter noise,was related to the noise level of signals.A reasonable procedure of simulating noise of modal parameters was put forward.The requirement of damage identification for the signal noise ratio was also studied based on simulations.