CAJ | 학술논문

结合随机子空间法（SSI）提出了环境激励下结构模态参数识别的改进ITD法。随机子空间法的识别精度高，其中数据的协方差计算可以保留原始数据中的所有信息，同时去除了噪声，得到的Toeplitz矩阵中的数据可以作为ITD法的输入数据，这样ITD法不再需要采用随机减量法或者自然激励技术（NExT法）进行前处理，从而避免了这两种前处理方法的不准确性带来的误差。通过环境振动下四层钢框架模型试验的位移响应，对提出的改进ITD法进行了验证。与ITD法相比，改进的ITD法明显提高了对频率和阻尼比等结构模态参数的识别精度，表明改进ITD法可应用于结构的模态参数识别；与SSI法相比，改进ITD法精度没有降低，同时缩短了计算时间，这将为该方法应用到结构的实时监测提供了可能。
결합수궤자공간법（SSI）제출료배경격려하결구모태삼수식별적개진ITD법。수궤자공간법적식별정도고，기중수거적협방차계산가이보류원시수거중적소유신식，동시거제료조성，득도적Toeplitz구진중적수거가이작위ITD법적수입수거，저양ITD법불재수요채용수궤감량법혹자자연격려기술（NExT법）진행전처리，종이피면료저량충전처리방법적불준학성대래적오차。통과배경진동하사층강광가모형시험적위이향응，대제출적개진ITD법진행료험증。여ITD법상비，개진적ITD법명현제고료대빈솔화조니비등결구모태삼수적식별정도，표명개진ITD법가응용우결구적모태삼수식별；여SSI법상비，개진ITD법정도몰유강저，동시축단료계산시간，저장위해방법응용도결구적실시감측제공료가능。
The system modal parameters identification under ambient excitation is becoming the focus of structural health monitoring.An improved ibrahim time domain (ITD)method was put forward,combined with stochastic subspace identification (SSI)method in order to achieve good identification accuracy.Through the model experiment of a four-story steel frame,it is proved that the improved ITD method is more accurate for the damping ratio and frequency identification than the ITD method.The improved ITD method can be applied to structural modal parameter identification under ambient excitation.Comparing with the SSI method,the precision is not lowered,while the time consuming in computation is reduced.It is possibille to apply the method to real-time monitoring of structures.