Free Vibration of Numerical and experimental study-Supported Cylindrical Steel Tanks

Abstract

The recent seismic events in Syria highlight the necessity of studying and evaluating the seismic response of structures to save lives. Liquid storage tanks have a major role, and their operational integrity must be maintained following seismic events. Therefore, it is essential to evaluate the performance and study the seismic behavior for its. In this research, the dynamic characteristics, natural frequencies, and model shapes of ground tanks near Damascus were studied using an experimental method. The ambient noise measurement-Nakamura 1989- is executed in the case of an empty tank. The obtained results were compared with the results of the 3D numerical model of the finite element method (FEM) for the study tank using ABAQUS software. In addition, two tanks in the filling case with two different slenderness ratios (T1=0.36, T2=0.82) have been studied to clear the effect of the slender ratio. The natural frequency of the convective and impulsive components has been found analytically based on the Eurocode and numerically using the finite element method. The Couple Acoustic Structure (CAS) method has been used to model the fluid-tank interaction. The results of the paper have shown the possibility of using the ambient noise measurement to estimate the response of ground tanks, as the convergence rate with the finite element method arrived at 83% in the case of empty tanks. Also, the CAS method can be used to find the natural frequency of convective and impulsive components. The convergence rate with the Eurocode arrives at 97% 98% for the convective frequency of the (T1) and (T2), respectively, and convergence of 95% and 88% for the impulsive frequency of (T1) and (T2), respectively. Finally, the importance of research can be summarized in contributing to avoiding the occurrence of the resonance condition by adapting the engineering design for the liquid tank system