环境激励下简支梁式结构的动力参数识别研究

Research on Dynamic Parameters Identification of Simply Supported Girder Structure Under Ambient Excitation

本文设计了一个简支梁式结构模型,运用特征系统实现算法,分别采用锤击激励、行车激励与环境激励的方法进行结构动力参数的识别,并对识别结果进行对比分析。在动力参数的识别过程中,采用环境激励时,由于系统信噪比较低有可能存在噪声模态,对此可以参照多个过程参数进行辨别。结果表明:在实验室条件下,基于环境激励的方法可以识别第1,3,4阶频率,满足工程要求,且识别精度与锤击激励、行车激励的识别结果相比差异不显著;试验结果没有识别出第2阶频率,应在工程测试中引起注意。

A simply supported structure model was designed in this paper.Based on the eigensystem realization algorithm,the structural dynamic parameters were identif ied respectively by hammer excitation,moving-vehicle excitation and ambient excitation.The results of recognition were compared and analyzed.In the process of identifying dynamic parameters,when ambient excitation is used,the noise modal may exist because of low system signal-to-noise ratio,which can be identif ied by multiple process parameters.The results show that under the laboratory conditions,the f irst,the third and the fourth order frequency can be identif ied based on the method of ambient excitation.The results meet the engineering requirement,and their recognition accuracy are not signif icant compared with the identif ication results of hammer excitation and moving-vehicle excitation.The test results did not identify the second order frequency,so attention should be paid to the engineering test.