scholarly journals The modal analysis of cylindrical steel tank with selfsupported roof filled with different level of liquid

2013 ◽  
Vol 12 (2) ◽  
pp. 205-212
Author(s):  
Daniel Burkacki ◽  
Michał Wójcik ◽  
Robert Jankowski

In technical branches, such as chemical or petroleum industries, cylindrical steel tanks are essential structures used for storage of liquid products. Therefore, their safety and reliability is essential, because any failure might have dangerous consequences, in extreme cases may even lead to an environmental disaster. The aim of the presented paper is to show the results of the modal analysis concerning the cylindrical steel tank with self-supported roof which has been constructed in northern Poland. The investigation was carried out with the use of the FEM commercial computer program Abaqus. The values of natural frequencies, as well as the natural modes, for different levels of liquid filling (empty tank, partly filled and tank fully filled) were determined in the study. The results of the study clearly indicate that the increase in the liquid level leads to the substantial decrease in the natural frequencies of the structure.

2014 ◽  
Vol 14 (3) ◽  
pp. 37-47 ◽  
Author(s):  
Daniel Burkacki ◽  
Robert Jankowski

Abstract Cylindrical steel tanks are very popular structures used for storage of products of chemical and petroleum industries. Earthquakes are the most dangerous and also the most unpredictable dynamic loads acting on such structures. On the other hand, mining tremors are usually considered to be less severe due to lower acceleration levels observed. The aim of the present paper is to show the results of the experimental study which has been conducted on a scaled model of a real tank located in Poland. The investigation has been carried out under different dynamic excitations (earthquakes and mining tremors) using the shaking table. The results of the study indicate that stored product may significantly influence the values of dynamic parameters and confirm that the level of liquid filling is really essential in the structural analysis. The comparison of the response under moderate earthquakes and mining tremors indicate that the second excitation may be more severe in some cases.


2019 ◽  
Vol 45 (2) ◽  
pp. 85-91
Author(s):  
Kostyantyn Burak ◽  
Vitaliy Kovtun ◽  
Mary Nychvyd

The purpose of this work is to increase the accuracy, quality and information content of geodetic surveys of vertical steel tanks by using modern geodetic equipment and creating algorithms for data processing of these observations. Method. In order to increase the information content of data for straightening, it is proposed to calculate the geometric parameters of vertical steel tanks not only in places where data are directly obtained through instrumental observations, but also at any point of the 3D surface of the tank. The paper describes an algorithm for creating a 3D surface of a tank by bicubic spline interpolation (BSI). Results on the basis of the conducted research, it was established that the developed algorithm could be used and the 3D-surface spatial coordinates were determined. The method of determining the geometric parameters of vertical steel tanks by using BSI is improved. Scientific novelty and practical significance. Bicubic spline interpolation (BSI) was used for the first time. It greatly increases the accuracy and informality of the results of the control. The practical significance is confirmed by the control of the geometric parameters of a vertical cylindrical steel tank with a nominal capacity of 75.000 m3 with a floating roof and a double wall of the LODS “Brody” company.


ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 1781-1788
Author(s):  
Özer Zeybek ◽  
Cem Topkaya ◽  
J. Michael Rotter

2019 ◽  
Vol 265 ◽  
pp. 07005
Author(s):  
Petr Chepur ◽  
Aleksandr Tarasenko ◽  
Vadim Krivorotov ◽  
Evgeniy Tikhanov ◽  
Alesya Gruchenkova

The article describes the particular qualities of application of a cylindrical steel tanks' and base foundation technical inspection method without removal of a protective covering. The model is formed and the basic parameters of an estimation of economic efficiency of carrying out of diagnostics are determined. The economic efficiency of application of the modern method of vertical steel tank examination is estimated. The high economic efficiency of the new technological method is substantiated in comparison with the traditional method. It is established that the advantage of using the innovative diagnostic method in comparison with the traditional method is fully manifested when it is necessary to maintain a large fleet of tanks. It is calculated that, given the design parameters, the savings in the use of the method proposed by the authors in the long term are 1773.2 million rubles compared with traditional. The use of a new technological method - the technology of diagnosing vertical steel tanks without removing the protective coating, allows to reduce the total cost of conducting diagnostics with a discount of 8.7 times. Dependences were obtained of the discounted volume of expenses on acquisition of the equipment and the subsequent diagnostics of vertical steel tanks on the operation time of the vertical steel tanks.


2012 ◽  
Vol 28 (1) ◽  
pp. 217-238 ◽  
Author(s):  
Zuhal Ozdemir ◽  
Mhamed Souli ◽  
M. Fahjan Yasin

In this paper, a fluid-structure interaction (FSI) algorithm of the finite element method (FEM), which can take into account the effects of geometric and material nonlinearities of the tank, buckling of the tank shell, and nonlinear sloshing behavior of the contained liquid, is utilized to evaluate the actual behavior of broad cylindrical steel tanks when subjected to strong earthquake motions. In order to clarify a key question—whether anchoring would prevent earthquake damage to tanks—numerical analyses are carried out on the same tank model having two different support conditions: anchored and unanchored. In addition to two horizontal components of ground motion, the vertical component is also taken into account in order to determine the relative importance of vertical ground motion in the behavior of tanks. The consistency of provisions presented in current design codes and numerical analysis results is evaluated.


Author(s):  
Ken Hatayama ◽  
Shinsaku Zama ◽  
Shoichi Yoshida

Abstract Microtremor observations measured the natural frequencies of the fluid-elastic-coupled shell plate vibration (bulging) in a large flat-bottomed cylindrical steel tank with a 125,000-m3 capacity. Five peaks appear in the observed microtremor spectral ratios of the top or mid-height of the shell plate to the bottom on the tank foundation. Comparing the spectral ratios to the solutions obtained by FEM eigenvalue analysis assuming a fixed base suggests that the five peaks are the bulging modes of (m, n)=(1, 1 to 5), where m and n denote the vertical order and the circumferential wavenumber, respectively. The measured non-soil-coupled natural frequencies from the spectral ratio agree fairly well with those obtained from FEM analysis. The measured natural frequencies of the fundamental mode (m=n=1) also agree well with those projected by a simplified equation developed under the assumption of a fixed base, which is adopted in the seismic codes of the Japanese Fire Service Act. This equation should provide a reliable soil-coupled natural frequency of the fundamental mode for a tank situated on firm ground in which the storage-soil-coupled effects are presumed weak. Additionally, a simple method is presented to determine the non-soil-coupled natural frequency of the fundamental mode from the observed microtremor spectral ratios without referencing the FEM eigenvalue solutions. This simple method works very well for the tank examined.


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