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1 – 10 of 837I. Gavrilyuk, M. Hermann, I. Lukovsky, O. Solodun and A. Timokha
The main purpose of this paper is to develop two efficient and accurate numerical analytical methods for engineering computation of natural sloshing frequencies and modes i the…
Abstract
Purpose
The main purpose of this paper is to develop two efficient and accurate numerical analytical methods for engineering computation of natural sloshing frequencies and modes i the case of truncated circular conical tanks.
Design/methodology/approach
The numerical‐analytical methods are based on a Ritz Treftz variational scheme with two distinct analytical harmonic functional bases.
Findings
Comparative numerical analysis detects the limit of applicability of variational methods in terms of the semi‐apex angle and the ratio between radii of the mean free surface and the circular bottom. The limits are caused by different analytical properties of the employed functional bases. However, parallel use of two or more bases makes it possible to give an accurate approximation of the lower natural frequencies for relevant tanks. For V‐shaped tanks, dependencies of the lowest natural frequency versus the semi‐apex angle and the liquid depth are described.
Practical implications
The methods provide the natural sloshing frequencies for V‐shaped tanks that are valuable for designing elevated containers in seismic areas. Approximate natural modes can be used in derivations of nonlinear modal systems, which describe a resonant coupling with structural vibrations.
Originality/value
Although variational methods have been widely used for computing the natural sloshing frequencies, this paper presents their application for truncated conical tanks for the first time. An original point is the use of two distinct functional bases.
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P.M. McConnell, S.F. Owens and R.A. Kamin
PHOENICS, a general 3‐D Navier‐Stokes computer program, was used to simulate cooling and freezing of jet fuel stored in airplane fuel tanks. A 3‐D analysis is required for fuel…
Abstract
PHOENICS, a general 3‐D Navier‐Stokes computer program, was used to simulate cooling and freezing of jet fuel stored in airplane fuel tanks. A 3‐D analysis is required for fuel tanks of arbitrary geometry exposed to time dependent and nonuniform boundary temperatures. The work reported in this paper concentrated on 2‐D simulations of fuel cooling and freezing in a wing tank and external (pylon) tanks as a step toward the 3‐D analysis. Significant progress has been made on obtaining plausible solutions over the entire range of conditions considered. The same model, with appropriate changes for fuel properties, could also be used to predict fuel heating in airplane fuel tanks during supersonic flight conditions.
Himanshukumar R. Patel and Vipul A. Shah
The purpose of this paper is to stabilize the type-2 Takagi–Sugeno (T–S) fuzzy systems with the sufficient and guaranteed stability conditions. The given conditions efficaciously…
Abstract
Purpose
The purpose of this paper is to stabilize the type-2 Takagi–Sugeno (T–S) fuzzy systems with the sufficient and guaranteed stability conditions. The given conditions efficaciously handle parameter uncertainties by the upper and lower membership functions of the type-2 fuzzy sets (FSs).
Design/methodology/approach
This paper reports on a relevant study of stable fuzzy controllers and type-2 T–S fuzzy systems and reported that the synthesis of controller for nonlinear systems described by the type-2 T–S fuzzy model is a key problem and it can be resolve to convex problems via linear matrix inequalities (LMIs).
Findings
The multigain fuzzy controllers are established to improve the solvability of the stability conditions, and the authors design multigain fuzzy controllers which have extensive information of upper and lower membership grades. Consequently, the authors derive the traditional stability condition in terms of LMIs. One simulation examples illustrate the effectiveness and robustness of the derived stabilization conditions.
Originality/value
The uncertain MIMO nonlinear system described by Type-2 Takagi-Sugeno (T-S) fuzzy model, and successively LMI approach used to determine the system stability conditions. The proposed control approach will give superior fault-tolerant control permanence under the actuator fault [partial loss of effectiveness (LOE)]. Also the controller robust against the unmeasurable process disturbances. Additionally, the statistical z-test are carried out to validate the proposed control approach against the control approach proposed by Himanshukumar and Vipul (2019a).
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Industries which, historically, have had to contend with severe corrosion problems have always been the first to investigate new materials. They had to, and 20 years ago…
Abstract
Industries which, historically, have had to contend with severe corrosion problems have always been the first to investigate new materials. They had to, and 20 years ago industries such as the textile, pulp and paper, metal refining and chemical manufacturing turned their attention to reinforced plastics.
Mohanad El‐Harbawi, Sa'ari Mustapha, S. Abdul Rashid, Thomas S.Y. Choong and Mohamed AL‐Shalabi
It is known that there are hazards associated with the storage, handling and use of liquefied petroleum gas. Storage process plants of dangerous substances define the set of risk…
Abstract
It is known that there are hazards associated with the storage, handling and use of liquefied petroleum gas. Storage process plants of dangerous substances define the set of risk sources. Release of chemical due to accident could be severe and poses an immediate effect to workers on‐site and communities off‐site as well as it causes adversely a potential effect on the environment. LPG is considered to be a very important fuel and chemical feed stock. The material has been involved in many major fires and explosions. This paper presents the most recent analysis techniques for evaluating several physical models. These models are used to calculate the physical effects of explosion and fire from LPG accidents and also to predict the affected area.
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Effect of rocket and launcher design parameters on the maximum height obtainable in vertical flight. Comparison of costs for single‐ and two‐stage rockets. If efficiencies of…
Abstract
Effect of rocket and launcher design parameters on the maximum height obtainable in vertical flight. Comparison of costs for single‐ and two‐stage rockets. If efficiencies of around 100,000 ft./lb. payload/lb. propellent can be realized in practice, small solid propellent rockets should prove economical for routine meterological use.
F.G. Rammerstorfer, W. Auli and F.D. Fischer
The present paper deals with the numerical calculation of the behaviour of vertical wind‐loaded cylindrical shells (large liquid storage tanks) with a very flexible bottom plate…
Abstract
The present paper deals with the numerical calculation of the behaviour of vertical wind‐loaded cylindrical shells (large liquid storage tanks) with a very flexible bottom plate resting on an elastic foundation. The base of the tank, i.e. the lower boundary of the shell and the bottom plate, may partially uplift due to the shell deformations under the dead load, a hydrostatic pressure and due to wind forces. This behaviour represents non‐linear boundary conditions of the tank wall. Hence, the stability of the wind‐loaded tank is extremely influenced by the uplift conditions. This non‐linear problem (large deformations and variable contact) is solved by the FE method.
Hamid Naseri, Tadeh Zirakian and Hossein Showkati
Vertical cylindrical welded steel tanks are typical thin-walled structures that are very susceptible to buckling under settlement. The major concern in the design of these…
Abstract
Purpose
Vertical cylindrical welded steel tanks are typical thin-walled structures that are very susceptible to buckling under settlement. The major concern in the design of these thin-walled structures is buckling failure. On this basis and by considering the findings of the previously reported research works, the stability performance of open-top steel tanks with various industrial applications under local support edge settlement is further investigated in this paper. This study aims to contribute to the current state-of-the-art in the design and retrofit of such thin-walled structures.
Design/methodology/approach
The buckling behaviors of numerous cylindrical shell models with various height-to-radius, radius-to-thickness and settlement span ratios are investigated through linear and nonlinear buckling analyses. The effects of addition of a top stiffening ring on the buckling behavior of cylindrical steel tanks are studied as well.
Findings
This parametric study demonstrates that the choice of the height-to-radius, radius-to-thickness and settlement span ratios as well as addition of the top stiffening ring can be quite effective on the stiffness and strength performances, deformations and stress distribution as well as intensity of vertical cylindrical welded steel tanks subjected to local support edge settlement.
Originality/value
This research endeavor was formulated on the basis of a comprehensive literature survey and demonstrates the relationship between geometrical as well as stiffening features and buckling stability performance of open-top tanks subjected to local support edge settlement and also provides practical recommendations for design and retrofit purposes.
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Jie Li, Jiyuan Wu, Chunlei Tu and Xingsong Wang
Automatic robots can improve the efficiency of liquefied petroleum gas (LPG) tank inspection and maintenance, but it is difficult to achieve high-precision spatial positioning and…
Abstract
Purpose
Automatic robots can improve the efficiency of liquefied petroleum gas (LPG) tank inspection and maintenance, but it is difficult to achieve high-precision spatial positioning and navigation on tank surfaces. The purpose of this paper is to develop a spatial positioning robotic system for tank inspection. The robot can accurately identify and track weld paths. The positioning system can complete robot’s spatial positioning on tank surfaces.
Design/methodology/approach
A tank inspection robot with curvature-adaptive transmission mechanisms is designed in this study. A weld path recognition method based on deep learning is proposed to accurately identify and extract weld paths. Integrated multiple sensors, the positioning system is developed to improve the robot’s spatial positioning accuracy. Experiments are conducted on a cylindrical tank to test weld seam tracking accuracy and spatial positioning performance of the robotic system. The practicality of the robotic system is then verified in field tests.
Findings
The robot can accurately identify and track weld seams with a maximum drift angle of 4° and a maximum offset distance of ±30 mm. The positioning system has excellent positioning accuracy and stability. The maximum angle and height errors are 3° and 0.08 m, respectively.
Originality/value
The positioning system can improve the autonomous performance of inspection robots and solve the problems of weld path recognition and spatial positioning. Application of the robotic system can promote the automatic inspection and maintenance of LPG tanks.
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M. Lukaniszyn and R. Unbehauen
The results of calculation of the 3D electrostatic field in a cylindrical tank provided with a system of vertical grounding rods are presented. The field intensities of the…
Abstract
The results of calculation of the 3D electrostatic field in a cylindrical tank provided with a system of vertical grounding rods are presented. The field intensities of the original tank without the grounding rods are very large, which may cause a spark discharge, even at a relatively small space‐charge density. The presented results involving the grounding rod system can be used to eliminate or reduce fire and/or explosion hazards.
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