CFD-Based Aeroelastic Analysis in Transonic Flow Regime

2004 ◽  
Author(s):  
Chunlei He ◽  
Sangbum Choi ◽  
D. Mirmirani ◽  
Chivey Wu
Keyword(s):  
Finite Element ◽  
Transonic Flow ◽  
Three Dimensional ◽  
General Purpose ◽  
Computational Results ◽  
Cfd Simulations ◽  
Aeroelastic Analysis ◽  
Wind Tunnel Data ◽  
Wing Structure ◽  
Unstructured Meshing

The aeroelastic instability behavior of the AGARD445.6 wing at transonic flight speed is investigated by using Finite Element-based unsteady CFD simulations and automated three-dimensional unstructured meshing. A general-purpose multidisciplinary computer program called STARS (Structural Analysis RoutineS), developed at NASA Dryden Flight Research Center is employed as the tool for this study. The computational results on flutter boundaries of the wing structure are compared with wind tunnel data, and have been found to be satisfactory.

Inviscid-Viscous Coupled Solution for Unsteady Flows Through Vibrating Blades: Part 2—Computational Results

1993 ◽  
Vol 115 (1) ◽  
pp. 101-109 ◽  
Author(s):  
L. He ◽  
J. D. Denton
Keyword(s):  
Unsteady Flow ◽  
Transonic Flow ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Computational Results ◽  
Flow Conditions ◽  
Viscous Effects ◽  
Blade Flutter ◽  
Coupled Solution

A quasi-three-dimensional inviscid-viscous coupled approached has been developed for unsteady flows around oscillating blades, as described in Part 1. To validate this method, calculations for several steady and unsteady flow cases with strong inviscid-viscous interactions are performed, and the results are compared with the corresponding experiments. Calculated results for unsteady flows around a biconvex cascade and a fan tip section highlight the necessity of including viscous effects in predictions of turbomachinery blade flutter at transonic flow conditions.

Modeling of Blades as Equivalent Beams for Aeroelastic Analysis

2003 ◽  
Author(s):  
David J. Malcolm ◽  
Daniel L. Laird
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Three Dimensional ◽  
Element Model ◽  
Detailed Model ◽  
Stiffness Matrices ◽  
Aeroelastic Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A procedure has been developed and tested to derive a set of one-dimensional beam properties that will duplicate the behavior of a full three-dimensional finite element model of a wind turbine blade. This allows the full features of a detailed model to be transferred to an aeroelastic code for dynamic simulation of the complete wind turbine. The process uses the NuMAD interface to generate an ANSYS® finite element model to which a set of six unit loads are applied at the tip. The displacement results are used in a series of MATLAB routines to extract the stiffness matrices of the desired beam elements. Tests have been carried out on a number of blades and the stiffness matrices incorporated into ADAMS® models of the blades and complete wind turbines.

scholarly journals Thermal Residual Stresses in Thermoplastic Composite Disc with Holes Using 3D-Fem

2014 ◽  
Vol 23 (4) ◽  
pp. 096369351402300
Author(s):  
Faruk Sen ◽  
Tuncer Koruvatan ◽  
Kemal Aldas
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
General Purpose ◽  
Thermoplastic Composite ◽  
3D Fem ◽  
Finite Element Software ◽  
Solution Processes ◽  
Thermal Residual Stresses

In this study thermal residual stresses were calculated for a composite disc with many holes using 3D-FEM. Most of previous studies related to thermal stresses and residual stresses of composite disc were performed as two dimensional, but present study was done using three dimensional modelling and FEM, firstly. The composite disc was thermoplastic matrix and steel fibres for reinforcement material as unidirectional for radial direction. Different uniform temperature distributions were subjected to the thermoplastic composite disc as thermal loads. Finite element method (FEM) was used to compute thermal residual stresses. For this purpose, the thermal stress analysis was carried out in two stages as elastic and elastic-plastic solutions. All modelling and solution processes were done using ANSYS finite element software which is known as a general purpose engineering simulation. According to obtained results, thermal residual stresses in thermoplastic composite disc were created by applied thermal loadings owing to the composite disc having different thermal expansions in radial and tangential directions.

Structural Finite Elements With High-Order Basis Functions

1991 ◽  
Author(s):  
Chad D. Balch
Keyword(s):  
Finite Element ◽  
Dimensional Space ◽  
Three Dimensional ◽  
General Purpose ◽  
High Order ◽  
Benchmark Problems ◽  
Shell Elements ◽  
Space Curves ◽  
Doubly Curved ◽  
Deformation Modes

Abstract In the p-version of the finite element method, convergence is achieved by increasing the polynomial order of the elements. This paper discusses high-order three-dimensional carved beam and shell elements which have been implemented in a general purpose p-version linear finite element code. The displacement and rotation fields are represented by polynomials up to ninth order. Beam axes are three-dimensional space curves, and shell midsurfaces are general doubly-curved surfaces. Results for linear static and modal analyses are presented. In particular, it is demonstrated that a relatively small number of elements provide highly accurate results for typical benchmark problems. The elements perform robustly, with no locking or spurious deformation modes.

Rockfall on the Slope of the Embankment of Finite Element Analysis of the Impact of the Impact

2011 ◽  
Vol 261-263 ◽  
pp. 1119-1123
Author(s):  
Zi Jian Wang ◽  
Sheng Xie Xiao
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Road Construction ◽  
General Purpose ◽  
Simulation Software ◽  
Initial State ◽  
Element Analysis ◽  
The Road ◽  
The Impact

This article in a typical road slope model as an example, through large-scale general-purpose finite element simulation software ANSYS/LS-DYNA rockfall on the slope of the roadbed impact for three-dimensional dynamic analysis in the roadbed, slope geological parameters and falling stone initial state is not at the same time on the roadbed impact the results of comparative analysis. The result is the mountain slope of the road construction project provides reference.

An Interfacing Software Package for Thermal Analysis: Application to Microelectronics

1989 ◽  
Vol 111 (1) ◽  
pp. 54-60 ◽  
Author(s):  
A. Hadim ◽  
A. T. Chang ◽  
A. Chu ◽  
A. Yskamp
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Finite Difference ◽  
Software Package ◽  
Three Dimensional ◽  
General Purpose ◽  
Element Mesh ◽  
Finite Element Program ◽  
Thermal Network ◽  
Element Program

A software package called: INterfacing Software for Thermal ANalysis (INSTAN) is developed to interface finite element general purpose programs with finite-difference thermal network analyzers for detailed analysis of complex thermal problems. The finite element mesh is used to generate the thermal network representation of the problem. INSTAN performs automatically the thermal network calculations and generates a complete input file for the thermal analysis program. The INSTAN software package is a powerful modeling tool which uses the preprocessing and postprocessing features available in a finite element program. It has also the flexibility and heat transfer calculation capabilities of a finite-difference program. It can handle problems with three-dimensional irregular geometries, time and temperature dependent properties, and anisotropic materials. The software possesses enhanced capabilities that make it suitable for thermal analysis of microelectronic equipment.

On Centrifugal Softening in Finite Element Method Rotordynamics

2013 ◽  
Vol 81 (1) ◽  
Author(s):  
Giancarlo Genta ◽  
Mario Silvagni
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Three Dimensional ◽  
General Purpose ◽  
Rotating Beam ◽  
Fem Modeling ◽  
Rotating System ◽  
Softening Effect

The centrifugal softening effect is an alleged and elusive reduction of the natural frequencies of a rotating system with increasing speed which is sometimes found in finite element rotordynamics. This reduction may, in some instances, be large enough to cause some of the natural frequencies to vanish, leading to a sort of elastic instability. Some doubts can, however, be cast on the phenomenon itself and on the mathematical models causing it to appear. The aim of the present work is to shed some light on centrifugal softening and to discuss the assumptions that are at the basis of three-dimensional FEM modeling in rotordynamics. One and two degrees of freedom models, such as the ones introduced by Rankine and Jeffcott, are first studied and then the classical rotating beam, ring, disk, and membrane are addressed. Some numerical models, built using the FEM, are then solved using both dedicated and general purpose codes. In all cases no strong centrifugal softening is found.

Analysis of a Caisson Retained Island

1988 ◽  
Vol 110 (2) ◽  
pp. 68-76
Author(s):  
E. Evgin ◽  
S. Lord ◽  
I. Konuk
Keyword(s):  
Finite Element ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
General Purpose ◽  
Two Dimensional ◽  
Nonlinear Analyses ◽  
Stress Strain ◽  
Finite Element Program ◽  
Stress Strain Relation ◽  
Element Program

The results of the two and three-dimensional, nonlinear analyses of a caisson retained island in the Beaufort Sea are presented. A hyperbolic stress-strain relation for soils has been implemented in a general purpose finite element program, ADINA, to carry out the analysis. Based on the comparisons of the results, conclusions were drawn about whether a two-dimensional analysis can be safely used to replace a three-dimensional analysis.

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