Study On Flow-induced Vibration Characteristics Of RCC Structure And Modal Parameter Identification

Roller compacted concrete dam(RCC)differs from normal dams as it has higher requirements about the building materials and construction methods.The vibration of hydraulic structures caused by flood discharge is a complex phenomena of RCC dams.Flood discharge structures may occursevere bibration,even distraction,influenced by the complex flood discharge loads.Research on the materials partition could improve the RCC dams stress diatribution.Launch the research about vibration mechanism are very important to the design and safe operation of RCC flood discharege structures.The main contents are as follows:Firstly,research on vibration mechanism of RCC structure caused by flow-induced.According to the design information,analyze the general layout,determined relevant parameters about numerical simulation of RCC dams,established numerical simulation models,calculate the stress and deformation of the arch dam at runtime in selected conditions by using the international large-general finite element software ANSYS.Then analyze distribution of stress and displacement,put forward the comments and suggestions about dam partition on this basis,design many different partitioning schemes about materials,do the stablility calculation after the dam partition,comparative analysis of stress and displacement results of the dam,come to the partition law whichi is conducive to the dam stable.Secondly,the technology of structural modal parameter identification under the ambient excitation,don't need to incent structure,only uses the data which is measured under environmental incentives.And this method is better than the traditional modal identification methods as it has low cost,does not affect the normal work and without human motivation,etc.Based on the ambient vibration test data,modal frequencies,damping ratios and mode shapes of the RCC dam were identified.Using the measured data of the water elasticity test under ambient excitation,the identified modal frequency and damping ratio of he time-domain methods: ITD,STD,the complex exponential method,the time series analysis of ARMA model and eigensystem realization algorithm(ERA),were compared.