| In the process of industrialization and urbanization,the demand for storage buildings is growing day by day.The interaction between storage material and silo body can induce damage deformation or even buckling of silo structure under earthquake,which changes its dynamic characteristics.In order to ensure the long-term storage and operation of silo structure,it is necessary to deeply study the dynamic characteristics of steel silo under the influence of storage material.In this paper,taking flat flat steel silo as the research object,the dynamic characteristics of the steel silo model under pulse excitation and the storage-steel silo model under white noise(WN)excitation are studied,in order to provide theoretical basis and experimental reference for the seismic performance and optimal design of steel silo structure.The main work and research contents are as follows:(1)The physical and mechanical properties of ceramsite materials were studied by Soil mechanics method.The weight,apparent density,porosity,grade,and size of the ceramic particles were measured.The Direct shear test test of ceramsite samples was carried out by strain controlled direct shear apparatus.According to the fitting formula of normal stress Shear strength curve,the cohesion of ceramsite is 15.08 KPa,and the internal friction angle is 33.66 °.(2)Conduct experimental modal analysis on the steel plate silo under pulse excitation,and identify the modal parameters of the structure using a combination of time and frequency domains.According to the amplitude frequency curve,the natural vibration frequency of the model was obtained by the peak picking method at around 113 Hz.The acceleration time history was identified by Hilbert transform,and the average damping ratio of the empty warehouse was 2.09%.At the same time,the reliability of the frequency response function was verified by combining the coherence function.(3)The dynamic characteristics tests of a storage steel silo model with different stacking heights under white noise excitation were carried out using a graded loading method.The modal frequencies,modal damping ratios,and normalized modal shapes of steel silo models with different storage heights were obtained through modal parameter identification methods.And study the absolute peak acceleration and dynamic amplification coefficient of the storage steel plate silo model under white noise excitation.(4)The influence of different stacking heights and input peak accelerations on the dynamic characteristics of the storage silo structure was studied.The results show that the change in input peak acceleration has little impact on the empty warehouse,and the modal parameters remain almost unchanged.The natural vibration frequency of the storage silo structure system is negatively correlated with the input peak acceleration and stacking height;The modal damping ratio increases with the increase of input peak acceleration,and shows a trend of first increasing and then decreasing with the increase of stack height;The changes in mass and stiffness caused by storage,as well as the interaction between storage and the silo,are important reasons for the changes in dynamic characteristics of the storage steel silo model. |
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