基于ITD法的光岳楼木结构模态参数识别

Modal Parameter Identification of Guangyue Tower's Wood Structure Based on the Method of ITD

结构模态参数识别是结构动力响应分析的前提和基础,其中自振频率是反应结构动力特性的重要模态参数指标.因此,准确计算自振频率是分析光岳楼的动力反应的关键.本文依据泰斯特动态监测设备实测测点的振动数据,采用ITD法计算得到了光岳楼木结构的自振频率,并与STD法和OP.Polylscf算法计算得到的光岳楼木结构的自振频率进行了比较.研究结果表明:采用ITD法和STD法计算得到的光岳楼木结构的第1阶频率比较接近,但与OP.Polylscf算法计算得到的光岳楼木结构的1阶频率相比略偏小,这主要由于光岳楼历经多次维修加固,致使其整体刚度有所增大.而采用ITD法和STD法计算光岳楼木结构的其他各阶频率均大于采用OP.Polylscf算法的计算结果,除了第3阶频率的误差大于10%外,其余各阶误差均小于10%,说明采用ITD法计算光岳楼木结构的自振频率具有较高的精度.

The modal parameter identification of structure is the prerequisite and basis for the analysis of structural dynamic response.Natural vibration frequency is important modal parameters of its structural dynamic characteristics.Hence,the accurately calculation of structure natural frequency is very important for analyzing structural dynamic response based on numerical method and assessing safety of the structure.This paper obtained the natural frequency of Guangyue Tower＇s wood structure based on the measured vibration data and using the method of ITD,which were compared with the results obtained by the method of STD and OP.Polylscf.The first order frequency of Guangyue Tower＇s wood structure is relatively close by the method of ITD and STD from the calculation results,but which is too small by the method of OP.Polylscf.The reason for this result mainly is the overall stiffness increased of Guangyue Tower after multiple maintenance and reinforcement.The other frequencies of Guangyue Tower＇s wood structure by the method of ITD and STD are more than the calculation results of the method of OP.Polylscf.The error of the rest of the order is within 10% but the third order frequency.This paper showed that the method of ITD has better precision to calculate the natural frequency of Guangyue Tower＇s wood structure compared to other methods.