Prediction of Blade Flutter in a Tuned Rotor

1985 ◽  
Author(s):  
Jianmin Xu ◽  
Zhaohong Song
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Rotating Blades ◽  
Multiple Degrees Of Freedom ◽  
Strip Theory ◽  
Blade Flutter ◽  
Good Agreement

This paper is about blade flutter in a tuned rotor. With the aid of the combination of three dimensional structural finite element method, two dimensional aerodynamical finite difference method and strip theory, the quasi-steady models in which two degrees of freedom for a single wing were considered have been extended to multiple degrees of freedom for the whole blade in a tuned rotor. The eigenvalues solved from the blade motion equation have been used to judge whether the system is stable or not. The calculating procedure has been formed and using it the first stage rotating blades of a compressor where flutter had occurred, have been predicted. The numerical flutter boundaries have good agreement with the experimental ones.

Finite-element analysis of axi-symmetric rotors

1969 ◽  
Vol 4 (3) ◽  
pp. 163-168
Author(s):  
H Stordahl ◽  
H Christensen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Engineering Problems ◽  
Symmetric Rotor ◽  
Practical Engineering ◽  
Element Method

The finite-element method (1) (2)∗ is increasingly used in the stress analysis of mechanical-engineering problems. It is the purpose of this paper to described how the finite-element method can be used as an effective tool in the design of rotors. Up to the present time this method has mainly been used in the analysis of two-dimensional problems. However, a special class of three-dimensional problems, namely axi-symmetric rotors, can be treated as a nearly two-dimensional problem. This paper summarizes the development of the finite-element method as applied to the analysis of the axi-symmetric rotor. A computer programme is then briefly described, and the application of the method to the solution of three examples taken from practical engineering experience are presented.

Dynamic stress analysis of rotating twisted and tapered blades

1980 ◽  
Vol 15 (3) ◽  
pp. 117-126 ◽  
Author(s):  
V Ramamurti ◽  
S Sreenivasamurthy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Extensive Analysis ◽  
Dynamic Stress Analysis ◽  
Skew Angles ◽  
Good Agreement

In this paper the finite element method has been used to determine the stresses and deformations of pre-twisted and tapered blades. Three-dimensional, twenty-noded isoparametric elements have been used for the analysis. Extensive analysis has been done for various pre-twist angles, skew angles, breadth to length ratios, and breadth to thickness ratios of the blades. Experiments were carried out to determine the stresses for the verification of the numerical results and they were found to be in good agreement.

Investigation into the Effect of the Nut Thread Run-Out on the Stress Distribution in a Bolt Using the Finite Element Method

2003 ◽  
Vol 125 (3) ◽  
pp. 527-532 ◽  
Author(s):  
J. W. Hobbs ◽  
R. L. Burguete ◽  
E. A. Patterson
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Dimensional Models ◽  
Three Dimensional Models

By means of comparing results from finite element analysis and photoelasticity, the salient characteristics of a finite element model of a nut and bolt have been established. A number of two-dimensional and three-dimensional models were created with varying levels of complexity, and the results were compared with photoelastic results. It was found that both two-dimensional and three-dimensional models could produce accurate results provided the nut thread run-out and friction were modeled accurately. When using two-dimensional models, a number of models representing different positions around the helix of the thread were created to obtain more data for the stress distribution. This approach was found to work well and to be economical.

A fully divergence-free finite element method for magnetohydrodynamic equations

2018 ◽  
Vol 28 (04) ◽  
pp. 659-695 ◽  
Author(s):  
Ralf Hiptmair ◽  
Lingxiao Li ◽  
Shipeng Mao ◽  
Weiying Zheng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Magnetohydrodynamic Equations ◽  
Divergence Free ◽  
Incompressible Magnetohydrodynamic Equations ◽  
Preconditioned Gmres ◽  
Energy Law ◽  
Element Method

We propose a finite element method for the three-dimensional transient incompressible magnetohydrodynamic equations that ensures exactly divergence-free approximations of the velocity and the magnetic induction. We employ second-order semi-implicit timestepping, for which we rigorously establish an energy law and, as a consequence, unconditional stability. We prove unique solvability of the linear systems of equations to be solved in every timestep. For those we design an efficient preconditioner so that the number of preconditioned GMRES iterations is uniformly bounded with respect to the number of degrees of freedom. As both meshwidth and timestep size tend to zero, we prove that the discrete solutions converge to a weak solution of the continuous problem. Finally, by several numerical experiments, we confirm the predictions of the theory and demonstrate the efficiency of the preconditioner.

scholarly journals Benchmark for the Coupled Magneto-Mechanical Boundary Value Problem in Magneto-Active Elastomers

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2380
Author(s):  
Philipp Metsch ◽  
Raphael Schiedung ◽  
Ingo Steinbach ◽  
Markus Kästner
Keyword(s):  
Finite Element ◽  
Boundary Value Problem ◽  
Boundary Value ◽  
Three Dimensional ◽  
Diffuse Interface ◽  
Two Dimensional ◽  
Benchmark Problem ◽  
Material Models ◽  
Lagrangian Finite Element ◽  
Good Agreement

Within this contribution, a novel benchmark problem for the coupled magneto-mechanical boundary value problem in magneto-active elastomers is presented. Being derived from an experimental analysis of magnetically induced interactions in these materials, the problem under investigation allows us to validate different modeling strategies by means of a simple setup with only a few influencing factors. Here, results of a sharp-interface Lagrangian finite element framework and a diffuse-interface Eulerian approach based on the application of a spectral solver on a fixed grid are compared for the simplified two-dimensional as well as the general three-dimensional case. After influences of different boundary conditions and the sample size are analyzed, the results of both strategies are examined: for the material models under consideration, a good agreement of them is found, while all discrepancies can be ascribed to well-known effects described in the literature. Thus, the benchmark problem can be seen as a basis for future comparisons with both other modeling strategies and more elaborate material models.

scholarly journals FINITE ELEMENT ANALYSIS OF SHADED POLE MOTOR BASED ON MAXWELL2D

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-115-1-220
Author(s):  
Adnan J. Kazem ◽  
◽  
Amer M. Ali ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Induction Motor ◽  
Single Phase ◽  
Two Dimensional ◽  
Element Analysis ◽  
Analytical Results ◽  
Dimensional Finite Element ◽  
Good Agreement

Shaded pole induction motor is one of the simplest and least expensive types of single-phase motors, but one of the most difficult to analyze. In this paper, we adopted a two-dimensional finite element method 2DFEM, which is one of the most accurate methods to analyze such motors. We used Ansys Maxwell2D software with assist of AutoCAD software in modeling and analyzing a reluctance-augmented shaded pole motor. The 2DFEM results of torques and currents for this motor obtained from Maxwell2D were compared with the analytical results and appeared a good agreement.

scholarly journals A pathway to desired functionalities in vertically aligned nanocomposites and related architectures

MRS Bulletin ◽  
2021 ◽  
Author(s):  
Aiping Chen ◽  
Quanxi Jia
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Interface Microstructure ◽  
Two Dimensional ◽  
Superconducting Properties ◽  
Multiple Degrees Of Freedom ◽  
Challenges And Opportunities ◽  
Vertically Aligned

AbstractEpitaxial vertically aligned nanocomposites (VANs) and their related architectures have shown many intriguing features that are not available from conventional two-dimensional planar multilayers and heterostructures. The ability to control constituent, interface, microstructure, strain, and defects based on VANs has enabled the multiple degrees of freedom to manipulate the optical, magnetic, electrochemical, electronic, ionic, and superconducting properties for specific applications. This field has rapidly expanded from the interest in oxide:oxide to oxide:metal, metal:nitride and nitride:nitride systems. To achieve unparalleled properties of the materials, three-dimensional super-nanocomposites based on a hybrid of VAN and multilayer architectures have been recently explored as well. The challenges and opportunities of VAN films are also discussed in this article.

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