CAJ | 학술논문

针对输电塔阻尼特性识别问题，采用EMD和EEMD方法分解输电塔气弹模型试验的加速度时程以得到IMF 模态，运用 EEMD 方法、改进的随机减量法和 Hilbert 变换法识别输电塔在各风速风向下的频率和阻尼，并探讨阻尼在顺线方向和横线方向随风速变化的分布特点。研究发现，基于 EEMD 方法比基于 EMD 方法分解的 IMF 时程振荡模态更清晰，基于 EMD 方法的结果存在着一定程度的模态混叠；输电塔顺线向频率随着风速的增大而呈减小趋势，顺线向阻尼随着风速的增大呈单调增加趋势，而横线向阻尼随风速变化的规律性不明显。
침대수전탑조니특성식별문제，채용EMD화EEMD방법분해수전탑기탄모형시험적가속도시정이득도IMF 모태，운용 EEMD 방법、개진적수궤감량법화 Hilbert 변환법식별수전탑재각풍속풍향하적빈솔화조니，병탐토조니재순선방향화횡선방향수풍속변화적분포특점。연구발현，기우 EEMD 방법비기우 EMD 방법분해적 IMF 시정진탕모태경청석，기우 EMD 방법적결과존재착일정정도적모태혼첩；수전탑순선향빈솔수착풍속적증대이정감소추세，순선향조니수착풍속적증대정단조증가추세，이횡선향조니수풍속변화적규률성불명현。
In order to identify the damping characteristics of transmission towers,empirical mode decomposition (EMD)and ensemble empirical mode decomposition (EEMD)were employed to obtain intrinsic mode functions (IMFs) of accelerations time histories obtained from aero-elastic model wind tunnel tests of a transmission tower.The frequency and damping of the tower under various wind velocities and wind azimuths were identified using EEMD,improved random decrement technique (RDT)and Hilbert transformation.The distribution characteristics of damping along wind velocities in the along-line direction and in the cross-line direction were also investigated.Results showed that the vibrating modes of IMFs obtained with EEMD are much clearer than those obtained with EMD;furthermore,the mode-mixing problem still exists to some level in the IMFs obtained with EMD;totally speaking,the natural vibrating frequencies of the tower in the along-line direction decrease with increase in wind velocity,whereas the damping of the tower in the along-line direction increase with increase in wind velocity;however,the varying law of the damping of the tower in the cross-line direction with respect to wind velocity is not obvious.