CAJ | 학술논문

为了量化工作模态分析的不确定度，以随机子空间识别为例，用两种方法对识别的固有频率和阻尼比不确定度进行量化：①用不同测试组识别的模态参数的数学期望和标准差衡量其整体大小和离散程度，构建模态参数的整体置信区间；②引入了以矩阵敏感性分析的单个测试组识别的模态参数不确定度量化方法，并构造带置信区间的稳定图。以菜园坝桥拱肋试验数据作为工程实例进行了验证。研究表明：构建的整体置信区间弥补了目前对模态参数的单一评价模式；带置信区间的稳定图能让测试者分辨出结构真实模态和虚假模态；两种方法能分别从整体和局部反映识别的模态参数不确定度；为评价用工作模态分析方法来识别的模态参数的可信程度提供了依据。
위료양화공작모태분석적불학정도，이수궤자공간식별위례，용량충방법대식별적고유빈솔화조니비불학정도진행양화：①용불동측시조식별적모태삼수적수학기망화표준차형량기정체대소화리산정도，구건모태삼수적정체치신구간；②인입료이구진민감성분석적단개측시조식별적모태삼수불학정도양화방법，병구조대치신구간적은정도。이채완패교공륵시험수거작위공정실례진행료험증。연구표명：구건적정체치신구간미보료목전대모태삼수적단일평개모식；대치신구간적은정도능양측시자분변출결구진실모태화허가모태；량충방법능분별종정체화국부반영식별적모태삼수불학정도；위평개용공작모태분석방법래식별적모태삼수적가신정도제공료의거。
In order to quantify the uncertainty for operational modal analysis (OMA),two methods were employed to estimate the uncertainty of natural frequencies and damping ratios identified by using stochastic subspace identification (SSI).Firstly,mathematical expectation and standard deviation of modal parameters identified from different sets were used to measure the overall size and dispersion, and the overall confidence intervals of modal parameters were constructed.Secondly,a method to quantify the uncertainty of modal parameters obtained from a single set through matrix sensitivity analysis was introduced,and the stabilization diagram with confidence intervals was established.The ambient vibration test of an arch rib of Caiyuanba Yangtze River Bridge was taken as an example.The study showed that the overall confidence intervals is a supplement to the existing single mode to assess modal parameters;the stabilization diagram with confidence intervals can help testers to distinguish the spurious modes from the system actual modes;two methods introduced can measure the uncertainty of the modal parameters from overall and local viewpoints,respectively;they provide a basis for assessing the credibility of the estimated modal parameters from OMA.