CAJ | 학술논문

针对现有结构模态参数识别方法平稳激励假定的不足，提出了一种非平稳激励下的结构模态参数识别方法。以白噪声调幅激励、调幅相关激励和频率幅值调制共三类非平稳随机激励为对象，采用演化谱理论推导了随机激励分段叠加后的均值和方差表达式，然后在此基础上对传统的随机减量法进行拓展，将非平稳激励下模态参数识别问题转化为结构自由振动曲线的模态参数识别，最后利用特征实现算法识别结构的模态参数。通过一个悬臂梁数值模型和两层实验室钢框架进行验证，识别结果表明运用该算法可以准确识别出非平稳激励下系统的固有频率和振型，且固有频率的识别误差在2％以内，具有较高的识别精度。
침대현유결구모태삼수식별방법평은격려가정적불족，제출료일충비평은격려하적결구모태삼수식별방법。이백조성조폭격려、조폭상관격려화빈솔폭치조제공삼류비평은수궤격려위대상，채용연화보이론추도료수궤격려분단첩가후적균치화방차표체식，연후재차기출상대전통적수궤감량법진행탁전，장비평은격려하모태삼수식별문제전화위결구자유진동곡선적모태삼수식별，최후이용특정실현산법식별결구적모태삼수。통과일개현비량수치모형화량층실험실강광가진행험증，식별결과표명운용해산법가이준학식별출비평은격려하계통적고유빈솔화진형，차고유빈솔적식별오차재2％이내，구유교고적식별정도。
Aiming at the shortcoming of the existing modal parametric identification method with the assumption of stationary excitations,a modal parametric identification method under non-stationary excitation was presented here based on the radom decrement method.Firstly,the variance and the mean of the excitations were derived on the basis of the evolutionary spectral amplitude modulation theory for white noise amplitude modulation excitation,the related excitation with amplitude modulation and the non-stationary excitation with frequency and amplitude modulation.Then,the traditional random decrement method was expanded,and the modal parametric identification problem under non-stationary excitation was converted into a modal parametric identification problem based on free vibration response curves of structures.Finally,the modal parameters were identified using the eigen-system realization algorithms.The method was verified through a numerical model of a cantilevered beam and a two-story steel frame tests.The identification results showed that the proposed method can accurately identify natural frequencies and vibration modal shapes of the two structures under non-stationary excitation and the identification error for natural frequencies is less than 2%,it has a higher identification accuracy.