基于子結(jié)構(gòu)中彎曲波的拉索索力識別方法

肖軍 代洋 張永水

摘要：以軸向受拉修正Timoshenko梁模型為理論依托，從波的角度對拉索子結(jié)構(gòu)的動力特性進(jìn)行研究，分別討論了近場波與行波，發(fā)現(xiàn)距離梁端一定距離或較高的頻段可不考慮近場波的影響?；诹航Y(jié)構(gòu)中的行波傳播特性，通過3個(gè)測點(diǎn)的頻域響應(yīng)，利用最小二乘法擬合得到波分量系數(shù)，再以擬合殘差最小為目標(biāo)進(jìn)行拉索索力和抗彎剛度的識別。通過拉索振動的數(shù)值模擬實(shí)驗(yàn)驗(yàn)證了方法的精確性，索力與抗彎剛度值識別誤差均不超過1%。相比傳統(tǒng)的頻率法，該方法基于子結(jié)構(gòu)索力識別，不受減震器和邊界條件的影響，而且可基于識別的子索段索力，通過靜力分析反推拉索各個(gè)位置的索力，同時(shí)，在各頻率采樣點(diǎn)處均能識別出相應(yīng)索力，減小了外部干擾對索力識別的影響。

關(guān)鍵詞：拉索子結(jié)構(gòu);彎曲波;最小二乘法;索力識別;抗彎剛度識別;噪音

中圖分類號：U441 文獻(xiàn)標(biāo)志碼：A 文章編號：20966717（2020）04013509

收稿日期：20191111

基金項(xiàng)目：中國交建特大科技研發(fā)項(xiàng)目（2019ZJKJ07）;湖南省交通運(yùn)輸廳科技項(xiàng)目（201615）

作者簡介：肖軍（1987 ），男，博士（后），主要從事橋梁施工監(jiān)控及橋梁加固研究，Email： sunflower001@foxmail.com。

Received：20191111

Foundation items：Science and Technology Specical Major Project of CCCC （No. 2019ZJKJ07）; Hunan Provincial Transportation Science and Technology Project（No. 201615）.

Author brief：Xiao Jun （1987 ）， PhD， main research interests： bridge construction monitoring and bridge reinforcement， Email： sunflower001@foxmail.com.

Cable force identification method based on bending wave in substructure

Xiao Jun1，2， Dai Yang3， Zhang Yongshui3

（1.CCCC Second Highway Engineering Co. Ltd.， Xian 710065， P.R. China; 2. School of Highway， Changan University， Xian 710064， P.R. China; 3.School of Civil Engineering， Chongqing Jiaotong University， Chongqing 400074， P.R. China）

Abstract： Based on the theory of the axial tension modified Timoshenko beam model， this paper studies the dynamic characteristics of the cable substructure from the perspective of waves， and discusses the nearfield wave and traveling wave separately. The effects of nearfield waves can be ignored when it near the beam end or at high frequencies. Based on the travelling wave propagation characteristics in the beam structure， the wave component coefficients were obtained by the least square fitting method， and then the cable force and bending stiffness were identified with the aim of minimizing the fitting residual. Subsequently， the accuracy of the method was verified by numerical simulation experiments of cable vibration， and the error of cable force identification did not exceed 1%. Compared with the traditional frequency method， this method is based on the substructure cable force identification， which is not affected by shock absorbers and boundary conditions. Furthermore， the identified subcable segment cable forces can be used to inversely push the cable forces at various locations through static analysis. At the same time， the corresponding cable force can be identified at each frequency sampling point， reducing the impact of external interference on cable force identification.

Keywords：cable substructure; bending wave; least square method; cable force estimation; bending stiffness identification; noise