بررسي جريان در ميراگرتلاطمي تنظيمي با استفاده از روش هيبريدي SPH-FEM

چكيده انگليسي :

Characteristics of flow in Tuned Sloshing Damper TSD Using a Hybrid SPH FEM Method Amin Karamnasab a karamnasab18@gmail com Date of submission July 18 2011 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mohammad Reza Chamani Ph D mchamani@cc iut ac ir Amir Mahdi Halabian Ph D mahdi@cc iut ac irAbstractCurrent trends in construction industry demands lighter structures which are also more flexible and having quitelow damping value The flexibility of the structures usually increases the failure possibilities and change to thestructural serviceability Tuned Sloshing Damper TSD is a technique to minimize the vibration of the structure TSDs are generally rectangular or circular containers filled with a liquid such as water and are installed at thehighest level of the structure The control force is produced from the dynamic pressure acting on lateral sides ofthe container due to the liquid oscillations inside the container In the present study a mesh free numerical method so called Smoothed Particle Hydrodynamic SPH isused to predict flow behavior inside TSD In this study a TSD equipped with screens subjected to a given baseexcitation was modeled employing SPH method and the results were compared with the existing experimentaldata Several parameters such as the force acting on the wall by the fluid wave height and free surface profile inthe container were estimated The length of the containers is varied between 0 50 to 1 5 meters and the height ofwater inside TSDs is varied between 10 to 320 millimeters Due to high capability of SPH method in simulatingthe problems with moving interface as well as extremely large deformation a wide range of excitation amplitudesand frequencies were studied The excitation amplitude varied between 0 5 to 1000 millimeters which are morethan ones used in the previous researches The response of SDOF and MDOF structures equipped with TSD isalso studied using a hybrid model containing SPH method and Finite Element Method FEM The proposedmodel used to evaluate the dynamic response of mentioned structures under large seismic excitations havingbroad range of frequencies Two MDOF structures with linear behavior were subjected to 3 earthquakeexcitations These structures equipped with multi TSDs and their characteristics are investigated for differentmass and frequency ratios The verification of SPH method was carried out for four cases of TSD under harmonic excitation Fairagreement is seen between SPH predictions and experimental observations identifying SPH method as a valuabletool for TSD design Also the ability of hybrid model in estimating the response of a SDOF structure under arandom excitation was proved by validating the modeling results with experimental data After verification aTSD was considered with length of 500 mm and different water height subjected to excitations of 10 and 40 mmamplitude It is shown when transfer waves occur in the container TSD is more capable to decrease the responseof structure In this situation the fluid mass is transferred along the container and the waves with suitable heightsare formed In part of structural analysis it was concluded that application of TSD can suppress the response ofboth studied structures although in some cases TSD intensifies the response of the structure The efficiency ofTSD is related to wave type which is formed in the container and also inherent features of the structures Theresults show that the optimum frequency and mass ratios are 0 9 and 0 08 respectively Key words tuned sloshing damper vibrational control hybrid model smoothed particlehydrodynamic finite element method wave

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بررسي جريان در ميراگرتلاطمي تنظيمي با استفاده از روش هيبريدي SPH-FEM

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