试件特性对地震模拟振动台控制性能影响研究(Ⅱ)——对地震记录再现精度的影响及实时补偿
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摘要
常规振动台系统共振频率为20 Hz,而试验试件1阶频率最大为8 Hz,在进行地震模拟振动台控制系统设计时将试件视为刚性体,二者存在较大差异.因此,振动控制系统控制频带窄、稳定性差,降低了地震记录再现精度.本文通过系统建模分析了试件质量、频率、阻尼等因素对振动台控制性能的影响.结果表明:试件各阶频率周围频带的输入波再现精度很低,出现不同程度的放大与削弱,最大可达3倍.针对这一问题设计了实时反力补偿算法以修正试件与台面相互作用对控制系统性能的影响,在保证系统稳定性的前提下提高了地震记录的再现精度.
The specimen is assumed to be a rigid mass in the design of the shaking table control system and the primary frequency of the specimen is about 8 Hz.However,the resonant frequency of a small-middle-sized shaking table is more than 20 Hz.Therefore,there is a big difference between the specimen and the shaking table system caused by the assumption of the rigid mass for the specimen.This results in the control system operating in a narrow frequency band and poor stability reducing the replaying precision of the recorded seismic waves.In this paper,the effects on the controlling performances caused by the quality,frequency and damping ratio of the specimens are investigated and analyzed.In the results,the replaying precision of the input seismic waves which the frequency is near the one of the specimen are poor,some of the inputs are amplified,and others are reduced.The maximum value is amplified more than 3 times compared to the input waves.For improving the above disadvantages caused by the interaction between the specimen and the shaking table,the real-time compensation of reaction algorithm is proposed for modifying the control performance.The replaying precision of the input seismic records is greatly improved under the good stability of the control system.
The specimen is assumed to be a rigid mass in the design of the shaking table control system and the primary frequency of the specimen is about 8 Hz.However,the resonant frequency of a small-middle-sized shaking table is more than 20 Hz.Therefore,there is a big difference between the specimen and the shaking table system caused by the assumption of the rigid mass for the specimen.This results in the control system operating in a narrow frequency band and poor stability reducing the replaying precision of the recorded seismic waves.In this paper,the effects on the controlling performances caused by the quality,frequency and damping ratio of the specimens are investigated and analyzed.In the results,the replaying precision of the input seismic waves which the frequency is near the one of the specimen are poor,some of the inputs are amplified,and others are reduced.The maximum value is amplified more than 3 times compared to the input waves.For improving the above disadvantages caused by the interaction between the specimen and the shaking table,the real-time compensation of reaction algorithm is proposed for modifying the control performance.The replaying precision of the input seismic records is greatly improved under the good stability of the control system.
引文
[1]BLONDET M,ESPARZA C.Analysis of shaking table-structure interaction effects during seismic simulation tests[J].Earthquake Engineering&Structural Dynamics,1988,16:473-490.
[2]SYMANS M,TWITCHELL B.System identification of a uniaxial seismic simulator[C]∥Proc.12th Engineering MechanicsConference.Reston:American Society of Civil Engineers,1998:758-761.
[3]TROMBETTI T L.Analytical modeling of a shaking table system[D]∥Houston:Department of Civil Engineering,RiceUniversity,1997:29-129.
[4]CONTE J P,TROMBETTI T L.Linear dynamic modeling of a uni-axial servo-hydraulic shaking table system[J].EarthquakeEngineering&Structural Dynamics,2000,29(9):1375-140.
[5]TROMBETTI T L,CONTE J P.Shaking table dynamics:results from a test-analysis comparison study[J].Journal ofEarthquake Engineering,2002,6(4):513-551.
[6]李振宝,唐贞云,周大兴,等.试件特性对地震模拟振动台控制性能影响Ⅰ—对系统稳定性的影响[J].北京工业大学学报,2010,36(8):1091-1098.LI Zhen-bao,TANG Zhen-yun,ZHOU Da-xing,et al.Effects on the earthquake simulation caused by the characteristics ofthe specimen in the shaking table tests-part 1:effects on the stability of the system[J].Journal of Beijing University ofTechnology,2010,36(8):1091-1098.(in Chinese)
[7]黄浩华.地震模拟振动台的设计与应用技术[M].北京:地震出版社,2008:59-76.
[8]MERRITT H E.Hydraulic control system[M].New York:Wiley,1967:199-246.
[9]CHOPRA A K.Dynamic of structures[M].Conferenia:Conferenia Prentice Hall,1995:15-32.
[2]SYMANS M,TWITCHELL B.System identification of a uniaxial seismic simulator[C]∥Proc.12th Engineering MechanicsConference.Reston:American Society of Civil Engineers,1998:758-761.
[3]TROMBETTI T L.Analytical modeling of a shaking table system[D]∥Houston:Department of Civil Engineering,RiceUniversity,1997:29-129.
[4]CONTE J P,TROMBETTI T L.Linear dynamic modeling of a uni-axial servo-hydraulic shaking table system[J].EarthquakeEngineering&Structural Dynamics,2000,29(9):1375-140.
[5]TROMBETTI T L,CONTE J P.Shaking table dynamics:results from a test-analysis comparison study[J].Journal ofEarthquake Engineering,2002,6(4):513-551.
[6]李振宝,唐贞云,周大兴,等.试件特性对地震模拟振动台控制性能影响Ⅰ—对系统稳定性的影响[J].北京工业大学学报,2010,36(8):1091-1098.LI Zhen-bao,TANG Zhen-yun,ZHOU Da-xing,et al.Effects on the earthquake simulation caused by the characteristics ofthe specimen in the shaking table tests-part 1:effects on the stability of the system[J].Journal of Beijing University ofTechnology,2010,36(8):1091-1098.(in Chinese)
[7]黄浩华.地震模拟振动台的设计与应用技术[M].北京:地震出版社,2008:59-76.
[8]MERRITT H E.Hydraulic control system[M].New York:Wiley,1967:199-246.
[9]CHOPRA A K.Dynamic of structures[M].Conferenia:Conferenia Prentice Hall,1995:15-32.
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