环境激励下泵站出水塔结构模态参数辨识研究

高扬程提水泵站的出水塔结构在水流的激励作用下易出现剧烈振动甚至由此造成破坏,为研究其振动特性需对其结构模态参数进行准确辨识。以甘肃景电二期工程总干六泵站的出水塔为例,在工作荷载激励下对其振动信号进行现场采集,根据实测的结构振动时程,利用随机子空间法和特征系统实现算法分别对出水塔结构的模态参数进行时域辨识,并将其辨识结果与ANSYS三维有限元模拟结果进行对比验证。结果表明:随机子空间法和特征系统实现算法均能准确辨识出水塔结构模态参数,其模拟结果与实验结果吻合较好。研究成果可为泵站出水塔结构的更新改造设计和安全运行监测提供理论依据,同时能够为灌区水工结构的模态参数辨识提供技术参考。

Identification of modal parameters of water2outlet tower of pumpingstation under operational excitation conditions

The wat er2outlet tow er of hig h2lift pumping station can v ibr ate serio usly and even fail under the ex citatio n o f flow. Inorder t o study the v ibration char acter istics of w ater2outlet t ow er, accurate identificatio n of its mo dal par amet ers is necessar y. Inthis paper, the v ibration signals o f a w ater2outlet tower under the operational ex citation conditio ns w ere co llected in the No. 6pumping statio n of Jing dian phase II project in Gansu Prov ince. Acco rding to the measured vibrat ion data, the modal parameter sof the w ater2o ut let tow er w ere identif ied using two t ime2domain identification metho ds, including the sto chastic subspace ident i2ficat ion and eig en sy stem r ealization alg or ithm. The identification results w ere com par ed w ith t he simulated results determinedby ANSYS finite element method. The results show ed that both metho ds can identify the mo dal par ameters of the water2outlettow er accurately and the identificat ion results ar e in go od ag reement w ith the simulat ion results o bt ained from ANSYS finite el2ement metho d. The research can not o nly pr ovide the t heo retical basis for the renewa l design and safe operation monito ring ofthe w ater2o ut let tow er, but also offer the technical r eferences fo r the identification of mo dal parameters o f the hydraulic struc2tur es in the ir rigation distr ict.