scholarly journals A New Method Based on Laplace Transform and Its Application to Stability of Pipe Conveying Fluid

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
H. B. Wen ◽  
Y. R. Yang ◽  
P. Li ◽  
Y. D. Li ◽  
Y. Huang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Present Method ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
Transformation Method ◽  
Critical Flow ◽  
Pipe Conveying Fluid ◽  
Pipes Conveying Fluid ◽  
Conveying Fluid

A new differential transformation method is developed in this paper and is applied for free vibration problem of pipes conveying fluid. The natural frequencies, critical flow velocities, and vibration mode functions of such pipes with several typical boundary conditions are obtained and compared with the results predicted by Galerkin method and finite element method (FEM) and with other results archived. The results show that the present method is of high precision and can serve as an analytical method for the vibration of pipes conveying fluid.

A Hybrid Method for Transverse Vibration of Multi-Span Functionally Graded Material Pipes Conveying Fluid with Various Volume Fraction Laws

2017 ◽  
Vol 09 (07) ◽  
pp. 1750095 ◽  
Author(s):  
Jiaquan Deng ◽  
Yongshou Liu ◽  
Wei Liu
Keyword(s):  
Hybrid Method ◽  
Transverse Vibration ◽  
Present Method ◽  
Natural Frequencies ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Functionally Graded ◽  
Graded Material ◽  
Pipes Conveying Fluid ◽  
Conveying Fluid

Both functionally graded materials (FGMs) and fluid-conveying pipes have wide applications in engineering communities. In this paper, the transverse vibration and stability of multi-span viscoelastic FGM pipes conveying fluid are investigated. Volume fraction laws including power law, sigmoid law and exponential law are introduced to describe the variations of material properties in FGM pipes. A hybrid method which combines reverberation-ray matrix method and wave propagation method is developed to calculate the natural frequencies, and the results determined by present method are compared with the existing results in literature. Then, a comparative study is performed to investigate the effects of fluid velocity, volume fraction laws and internal damping on transverse vibration and stability of the FGM pipes conveying fluid. The results demonstrate that the present method has high precision in dynamic analysis of multi-span pipes conveying fluid. It is also found that natural frequencies of FGM pipes can be adjusted by devising the volume fractions laws. This particular feature can be tailored to fulfill the special applications in engineering.

Two parameters affecting the dynamics characteristics of a uniform-conical assembled pipe conveying fluid

2016 ◽  
Vol 23 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Zhang Zijun ◽  
Liu Yongshou ◽  
Han Tao
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Limited Range ◽  
Critical Flow ◽  
Pipe Conveying Fluid ◽  
Critical Flow Velocity ◽  
Galerkin Approach ◽  
Two Parameters ◽  
Conveying Fluid ◽  
Uniform Fluid

A modified Galerkin approach is employed to calculate the dynamic characteristics of a complex non-uniform fluid-conveying pipe assembled by a uniform and a conical segment. The effects of two geometric parameters (length ratio of the uniform part and conical truncation factor) on the dynamic stability are studied. Results prove that for the assembled fluid-conveying pipe 1) when fluid enters the pipe from the thinner end, the natural frequencies are higher than those when it enters from the wider end; 2) the critical flow velocity increases linearly with the increase of the uniform part ratio, while it decreases squarely with the increase of the conical truncation factor in a limited range and 3) the clamp-pined non-uniform pipe has a higher dimensionless critical velocity than the pin-clamped pipe when fluid enters from the wider end.

Vibration and Stability of Helical Pipes Conveying Fluid

1987 ◽  
Vol 109 (4) ◽  
pp. 402-410 ◽  
Author(s):  
C.-N. Fan ◽  
W.-H. Chen
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Mode Shapes ◽  
Critical Flow ◽  
Helical Pipe ◽  
End Conditions ◽  
Finite Element Procedure ◽  
Pipes Conveying Fluid ◽  
Conveying Fluid ◽  
Flow Velocities

This paper presents an accurate finite element procedure for the vibration and stability analysis of helical pipe conveying fluid. The kinematics of the helical pipe are derived including the effects of arbitrary curvatures and torsions in a nonorthogonal helical coordinate system. The equations of motion are derived from the Hamilton’s principle for mass transport system and the shear deformation and rotary inertia are also considered. The 3-node space-curved isoparametric element is used. The natural frequencies, mode shapes and critical flow velocities of buckling are studied for different end conditions. The significant influence of torsion effects on the calculation of natural frequencies and critical flow velocities is found. To demonstrate the validity and accuracy of the techniques developed, several numerical examples are illustrated.

scholarly journals NONLINEAR DYNAMIC ANALYSIS OF ROTATING PIPE CONVEYING FLUID BY THE FINITE ELEMENT METHOD

Transport ◽  
2003 ◽  
Vol 18 (5) ◽  
pp. 224-228 ◽  
Author(s):  
Marijonas Bogdevičius
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Nonlinear Response ◽  
Fluid Velocity ◽  
Nonlinear Dynamic Analysis ◽  
Angular Speed ◽  
Pipe Conveying Fluid ◽  
The Finite Element Method ◽  
Conveying Fluid ◽  
Element Method

The rotating pipe conveying fluid is considered. Non-linear (geometrical non-linearity) equation of the motion of the pipe is derived using the finite element method. The equation of motion is derived based of the following assumptions: fluid is incompressible and inviscid; rotory inertia and shear deformation of the pipe are neglected. The sources of parametric vibration are: fluid velocity and pressure, angular speed of pipe. The possibility to solve a nonlinear response problem including sub-and/or super-harmonic using the finite element method is shown. Numerical results are derived considering the rotating cantilevered pipe conveying fluid. All matrices and vectors of the finite element method are derived by the symbolic computation system Maple.

scholarly journals Modeling and Eigenfrequency Analysis of Sound-Structure Interaction in a Rectangular Enclosure with Finite Element Method

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Samira Mohamady ◽  
Raja Kamil Raja Ahmad ◽  
Allahyar Montazeri ◽  
Rizal Zahari ◽  
Nawal Aswan Abdul Jalil
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Active Noise Control ◽  
Interior Noise ◽  
Rectangular Enclosure ◽  
Sound Structure ◽  
Flexible Panel ◽  
Experimental Works ◽  
Element Method

Vibration of structures due to external sound is one of the main causes of interior noise in cavities like automobile, aircraft, and rotorcraft, which disturb the comfort of passengers. Accurate modelling of such phenomena is required in eigenfrequency analysis and in designing an active noise control system to reduce the interior noise. In this paper, the effect of periodic noise travelling into a rectangular enclosure is investigated with finite element method (FEM) using COMSOL Multiphysics software. The periodic acoustic wave is generated by a point source outside the enclosure and propagated through the enclosure wall and excites an aluminium flexible panel clamped onto the enclosure. The behaviour of the transmission of sound into the cavity is investigated by computing the modal characteristics and the natural frequencies of the cavity. The simulation results are compared with previous analytical and experimental works for validation and an acceptable match between them were obtained.

scholarly journals Dynamics Characteristics of Blast Furnace Shell

2011 ◽  
Vol 2-3 ◽  
pp. 1018-1020
Author(s):  
De Chen Zhang ◽  
Yan Ping Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blast Furnace ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Theoretical Foundation ◽  
Structural Mechanics ◽  
Mode Shapes ◽  
The Future ◽  
Element Method

Finite element method and structural mechanics method are used to study the blast furnace shell modal analysis and the natural frequencies and mode shapes have been calculated. The two methods were compared and validated , and the results provide a theoretical foundation for the anti-vibration capabilities design of blast furnace shell in the future .

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