DYNAMIC ANALYSIS OF FULLY ANCHORED CIRCULAR CYLINDRICAL LIQUIDS’ STORAGE STEEL TANKS USING FINITE ELEMENT METHOD

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Hanadi Abdulridha Lateef ◽  
Abdulamir Atalla
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Elastic Shell ◽  
Shell Element ◽  
Liquid Level ◽  
Mode Shapes ◽  
Rigid Base ◽  
Steel Tanks ◽  
Shell Finite Element

A vibration analysis of circular cylindrical steel liquid storage tanks anchored to rigid base is conducted. Empty, partially and completely liquid filled tanks are considered as well as tanks composed of two courses using ANSYS 11.0 finite element package. The tank wall is modeled using linear elastic shell finite element and a new method, based on the added mass approach, is developed to model the effect of the contained liquid. In this method the properties of the shell element is modified to include the effect of the contained liquid. The analysis includes four tank case studies which are empty, fully filled with water, and filled with changeable liquid level in addition to study the effect of the variable thickness of tank on the natural frequencies and mode shapes. The results show that the natural frequency of completely filled tall tank may be less by 70.7% than the natural frequency of empty tank. It is also found that a maximum value of natural frequency can be obtained when the lower thick course consists 0.75 of tank height and its thickness is four times that of the upper one. The natural frequencies decrease with the increasing in liquid level for tall tank. The natural frequency of completely filled tank is less by 70.7% than the natural frequency of empty tank.

Investigation of stiffness of small wind turbine blade based on vibration analysis technique

2019 ◽  
Vol 44 (1) ◽  
pp. 49-59
Author(s):  
Nilesh Chandgude ◽  
Nitin Gadhave ◽  
Ganesh Taware ◽  
Nitin Patil
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Natural Frequency ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Element Analysis ◽  
Finite Element Software ◽  
Small Wind Turbine

In this article, three small wind turbine blades of different materials were manufactured. Finite element analysis was carried out using finite element software ANSYS 14.5 on modeled blades of National Advisory Committee for Aeronautics 4412 airfoil profile. From finite element analysis, first, two flap-wise natural frequencies and mode shapes of three different blades are obtained. Experimental vibration analysis of manufactured blades was carried out using fast Fourier transform analyzer to find the first two flap-wise natural frequencies. Finally, the results obtained from the finite element analysis and experimental test of three blades are compared. Based on vibration analysis, we found that the natural frequency of glass fiber reinforced plastic blade reinforced with aluminum sheet metal (small) strips increases compared with the remaining blades. An increase in the natural frequency indicates an increase in the stiffness of blade.

A Novel Shell Element for Quasi-Static and Natural Frequency Analysis of Textile Composite Structures

2014 ◽  
Vol 81 (8) ◽  
Author(s):  
Wu Xu ◽  
Anthony M. Waas
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Composite Structures ◽  
Repeat Unit ◽  
Three Dimensional ◽  
Shell Element ◽  
Textile Composite ◽  
Shell Finite Element ◽  
Three Dimensional Finite Element ◽  
Natural Frequency Analysis

A shell element for analysis of textile composite structures is proposed in this paper. Based on the embedded element method and solid shell concept, the architecture, geometry, and material properties of a repeat unit cell (RUC) of textile composite are embedded in a single shell finite element. Flat and curved textile composite structures are used to apply and verify the present shell element. The deformation and natural frequency obtained by the present shell element are compared against those computed from full three-dimensional finite element analyses. It is shown that the proposed shell element is efficient, simple, and reliable for textile composite structural analysis.

scholarly journals Effects of the Radius of Curvature on Natural Frequency and Mode Shape

2019 ◽  
Vol 7 (12) ◽  
Author(s):  
Can Gonenli ◽  
Hasan Ozturk ◽  
Oguzhan Das
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Finite Element Program ◽  
Plane Theory ◽  
Element Type

In this study, the effect of radius of curvature on the natural frequency of isotropic square thin plate is investigated. The models examined are obtained by simply changing the radius of curvature by keeping the length constant from the flat plate to the semicircle model. The free vibration analysis of the plates fixed on two straight edges is performed by the finite element method. As a finite element type, the four-node quadrilateral rectangular element type, which has a total of 24 generalized coordinates, is used. Out-of-plane theory and in-plane theory are used together to form the curve model. The accuracy and validity of the theory are controlled with the data obtained from the finite element program. The effect of the curvature radius on the first five natural frequencies and the mode shapes of these natural frequencies is given in tables and graphs.

Three Dimensional Finite Element Analysis of Transverse Free Vibration of Self-Pierce Riveting Beam

2007 ◽  
Vol 344 ◽  
pp. 647-654 ◽  
Author(s):  
Xiao Cong He ◽  
Ian Pearson ◽  
Ken W. Young
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Self-pierce riveting (SPR) is nowadays widely used in the car manufacturing industry where aluminium alloys are used for body construction. For the design of mechanical structures, formed by the joining of component parts, a knowledge of the vibration characteristics of different joint types (adhesive bonding, spot welding, SPR etc) is essential. The free transverse vibration characteristics of single lap-jointed encastre SPR beams are investigated theoretically in this paper using the three dimensional finite element method (FEM). Numerical examples are provided to show the influence on the natural frequencies, natural frequency ratios and mode shapes of these beams caused by variations in the material properties (E and υ) of the sheet material. It is shown that the transverse natural frequencies of single lap jointed encastre SPR beams increases significantly as the Young’s Modulus of the sheets increases, but only slight changes are encountered for variations of Poisson’s Ratio. It is found that an exponential curve gives an acceptable fit to the relationship between natural frequency and Young’s Modulus. As expected, odd modes shapes were found to be symmetrical about the mid-length position and even modes were anti-symmetrical.

scholarly journals Prediction of vibration induced damage in photovoltaic modules during transportation: finite element model and field study

2021 ◽  
Author(s):  
Umang Desai ◽  
Devan Vasudevan ◽  
Anil Kottantharayil ◽  
Aparna Singh
Keyword(s):  
Finite Element ◽  
Solar Cells ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Electrical Performance ◽  
Mode Shapes ◽  
Maximum Displacement ◽  
Photovoltaic Modules ◽  
Mechanical Handling ◽  
Pv Modules

Abstract The transportation of the photovoltaic (PV) modules involves excessive vibrations and shocks. These dynamic loads can crack the solar cells and glass of the PV modules. The cracks generated in solar cells during the transportation phase may not always have immediate implications on the electrical performance of the PV modules. However, in the long-run, cracks generated during transportation of the modules may propagate during operation in field due to wind load, snow load and thermal stresses. The propagation of cracks may create electrical isolation in the cells of a PV module, which can cause loss of electrical power. Therefore, it is important to minimize the damage in PV modules due to transportation and mechanical handling. In this work, PV modules have been transported in packaging following the industry practices to cover a distance of 270 km with accelerometers attached on several modules. Finite element (FE) modelling has been used to calculate natural frequency of vibration for the assembly of the PV modules by simulating the conditions close to the actual transportation experiment. This study shows that transportation makes the modules vibrate at their natural frequency. The first four natural frequencies of vibration calculated through the FE simulations match well with the peaks observed in the power spectral density profiles experienced by PV modules during transportation. Mode shapes corresponding to the first four natural frequencies have also been visualized to identify the contours with maximum displacement. It is hypothesized that out of all the cells, those falling within the contour of maximum displacement would have higher propensity for damage during the transportation. The results presented here can be useful for PV community to improve the packaging methodology, dimensions and material selection of the photovoltaic modules.

scholarly journals Compression and impact characterization of helical and slotted cylinder springs

2014 ◽  
Vol 3 (2) ◽  
pp. 268
Author(s):  
Ahmed Ibrahim Razooqi ◽  
Hani Aziz Ameen ◽  
Kadhim Mijbel Mashloosh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequency ◽  
Transient Response ◽  
Natural Frequencies ◽  
Circular Cross Section ◽  
Mode Shapes ◽  
Helical Spring ◽  
Ansys Software ◽  
Element Analysis

Helical and slotted cylinder springs are indispensable elements in mechanical engineering. This paper investigates helical and slotted cylinder springs subjected to axial loads under static and dynamic conditions. The objective is to determine the stiffness of a circular cross-section helical coil compression spring and slotted cylinder springs with five sizes and dynamic characteristics. A theoretical and finite element models are developed and presented in order to describe the various steps undertaken to calculate the springs stiffnesses. Five cases of the springs geometric are presented. A finite element model was generated using ANSYS software and the stiffness matrix evaluated by applying a load along the springs axis, then calculating the corresponding changes in deformation. The stiffness is obtained by solving the changes of load and deformation. The natural frequencies, mode shapes and transient response of springs are also determined. Finally, a comparison of the stiffnesses are obtained using the theoretical methods and those obtained from the finite element analysis were made and good agreement are evident and it can be found that the stiffness of spring for the slotted cylinder spring is much larger than that for helical spring and the stiffness for slotted cylinder spring increases with the number of slots per section. Natural frequencies, mode shape and transient response of helical spring and slotted cylinder spring have been represented in ANSYS software and results have been compared and it found that the natural frequency has also increased in the same proportion of stiffness because the natural frequency is directly proportional to the stiffness for all the cases that have been studied. Keywords: ANSYS, Finite Element Analysis, Helical Spring, Slotted Cylinder Spring, Stiffness.

Effect of crack on free vibration of a pre-stressed curved plate

2021 ◽  
pp. 095440622199486
Author(s):  
Can Gonenli ◽  
Hasan Ozturk ◽  
Oguzhan Das
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Natural Frequency ◽  
Present Model ◽  
Mode Shapes ◽  
Load Parameter ◽  
Flexible Plate ◽  
Cantilever Plate ◽  
Finite Element Software ◽  
Aspect Ratios

In this study, the effect of crack on free vibration of a large deflected cantilever plate, which forms the case of a pre-stressed curved plate, is investigated. A distributed load is applied at the free edge of a thin cantilever plate. Then, the loading edge of the deflected plate is fixed to obtain a pre-stressed curved plate. The large deflection equation provides the non - linear deflection curve of the large deflected flexible plate. The thin curved plate is modeled by using the finite element method with a four-node quadrilateral element. Three different aspect ratios are used to examine the effect of crack. The effect of crack and its location on the natural frequency parameter is given in tables and graphs. Also, the natural frequency parameters of the present model are compared with the finite element software results to verify the reliability and validity of the present model. This study shows that the different mode shapes are occurred due to the change of load parameter, and these different mode shapes cause a change in the effect of crack.

scholarly journals Effects of Elliptical Hole on the Correlation of Natural Frequency with Buckling Load of Basalt Laminates Composite Plates

2020 ◽  
Vol 27 (1) ◽  
pp. 216-225
Author(s):  
Buntheng Chhorn ◽  
WooYoung Jung
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Basalt Fiber ◽  
Orientation Angle ◽  
Elliptical Hole ◽  
Composite Plates ◽  
Buckling Load ◽  
Mode Shapes ◽  
Geometric Ratio

AbstractRecently, basalt fiber reinforced polymer (BFRP) is acknowledged as an outstanding material for the strengthening of existing concrete structure, especially it was being used in marine vehicles, aerospace, automotive and nuclear engineering. Most of the structures were subjected to severe dynamic loading during their service life that may induce vibration of the structures. However, free vibration studied on the basalt laminates composite plates with elliptical cut-out and correlation of natural frequency with buckling load has been very limited. Therefore, effects of the elliptical hole on the natural frequency of basalt/epoxy composite plates was performed in this study. Effects of stacking sequence (θ), elliptical hole inclination (ϕ), hole geometric ratio (a/b) and position of the elliptical hole were considered. The numerical modeling of free vibration analysis was based on the mechanical properties of BFRP obtained from the experiment. The natural frequencies as well as mode shapes of basalt laminates composite plates were numerically determined using the commercial program software (ABAQUS). Then, the determination of correlation of natural frequencies with buckling load was carried out. Results showed that elliptical hole inclination and fiber orientation angle induced the inverse proportion between natural frequency and buckling load.

Vibration-based delamination evaluation in GFRP composite beams using ANN

2021 ◽  
pp. 096739112110033
Author(s):  
TG Sreekanth ◽  
M Senthilkumar ◽  
S Manikanta Reddy
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Composite Structures ◽  
Composite Beams ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Aviation Industry ◽  
Frequency Data ◽  
Fiber Reinforced ◽  
Back Propagation Algorithm

Delamination is definitely an important topic in the area of composite structures as it progressively worsens the mechanical performance of fiber-reinforced polymer composite structures in its service period. The detection and severity analysis of delaminations in engineering areas like the aviation industry is vital for safety and economic considerations. The existence of delaminations varies the vibration characteristics such as natural frequencies, mode shapes, etc. of composites and hence this indication can be effectively used for locating and quantifying the delaminations. The changes in vibration characteristics are considered as inputs for the inverse problem to determine the location and size of delaminations. In this paper Artificial Neural Network (ANN) is used for delamination evaluationof glass fiber-reinforced composite beams using natural frequency as typical vibration parameter. The Finite Element Analysis is used for generating the required dataset for ANN. The frequency-based delamination prediction technique is validated by finite element models and experimental modal analysis. The results indicate that the ANN-based back propagation algorithm can predict the location and size of delaminations in composites with good accuracy for numerical natural frequency data but the accuracy is comparitivelyless for experimental natural frequency data.

Vibration of Beams with a Single Delamination under Axial Loading

2011 ◽  
Vol 675-677 ◽  
pp. 477-480
Author(s):  
Dong Wei Shu
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Analytical Solutions ◽  
Axial Load ◽  
Natural Frequencies ◽  
Axial Loading ◽  
Composite Beams ◽  
Mode Shapes ◽  
Equilibrium Conditions ◽  
Monotonic Relation

In this work analytical solutions are developed to study the free vibration of composite beams under axial loading. The beam with a single delamination is modeled as four interconnected Euler-Bernoulli beams using the delamination as their boundary. The continuity and the equilibrium conditions are satisfied between the adjoining beams. The studies show that the sizes and the locations of the delaminations significantly influence the natural frequencies and mode shapes of the beam. A monotonic relation between the natural frequency and the axial load is predicted.

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