Three-Dimensional Finite Element Analyses for Pyramidal Three-Roll Bending Process

2009 ◽  
Author(s):  
Zhengkun Feng ◽  
Henri Champliaud ◽  
Thien-My Dao
Keyword(s):  
Finite Element ◽  
Manufacturing Industry ◽  
Time Integration ◽  
Three Dimensional ◽  
Rigid Bodies ◽  
Francis Turbine ◽  
Molding Process ◽  
Shell Elements ◽  
Roll Bending ◽  
Bending Process

Many applications of conical roll bending can be found in manufacturing industry, such as rolling a conical segment of a wind turbine tower or an alternative process of molding a large crown for a Francis turbine. This molding process could be achieved by assembling several conical segments. For the purpose of using cylindrical rolls or reusing the existing conical rolls of the kinematical conical roll bending process for non-kinematical conical roll bending process, attachments were proposed in order to reduce the velocity at the top edge of the plate. In contrast with a kinematical conical roll bending machine where no sliding exists between the plate and the rolls, the contact surface near the top edge of the plate of the three driving rolls of a non-kinematical conical roll bending machine slides on the plate due to the friction between the attachments and the plate. Therefore, the appropriate velocity at the top edge of the plate corresponding to that of the kinematical conical roll bending process can be obtained. This paper deals with the simulation analyses of the non-kinematical multi-pass conical roll bending process based on the finite element method, for example, the analyses of the applied force on the pressing roll. The components of the roll bending machine, such as the rolls and the attachments, etc. were assumed to be rigid bodies and the 4-node shell elements were used in the modeling. Bilinear material properties were used for the elasto-plasticity of the plate. Automatic node-surface contacts were chosen on the interfaces between the plate and the rigid bodies. The nonlinear equations which represent the structural dynamics with large displacement were resolved using explicit time integration. The simulations were performed under the well-known ANSYS/LS-DYNA environment. A well bent cone was obtained and compared very well with the ideal cone. The numerical simulation results show that the bent cone depends on the static and dynamic friction coefficients for a geometrical configuration with an appropriate span of the outer rolls.

Comparison Between Numerical Simulation and Experimentation of Asymmetrical Three-Roll Bending Process

2010 ◽  
Author(s):  
Zhengkun Feng ◽  
Henri Champliaud
Keyword(s):  
Structural Dynamics ◽  
Metal Forming ◽  
Plastic Material ◽  
Time Integration ◽  
Material Model ◽  
Rigid Bodies ◽  
The Finite Element Method ◽  
Shell Elements ◽  
Roll Bending ◽  
Bending Process

Three-roll bending processes are widely used in metal forming manufacturing due to simple configurations. Asymmetrical three-roll bending is one of the processes. This paper deals with the simulation analyses based on the finite element method for cylindrical production. The components of the roll bending machine, such as the rolls were assumed to be rigid bodies and the 4-node shell elements were used in the modeling. The tensile test of the material was simulated to determine the elasto-plastic material model of the plate. Automatic node-surface contacts were chosen for the interfaces between the plate and the rigid bodies. The nonlinear equations which represent the structural dynamics with large displacement were resolved using explicit time integration. The simulations were performed under the well-known ANSYS/LS-DYNA environment. The numerical results agree well with the experimental ones.

A Finite Element for the Analysis of Shell Intersections

1996 ◽  
Vol 118 (4) ◽  
pp. 399-406 ◽  
Author(s):  
W. J. Koves ◽  
S. Nair
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Three Dimensional ◽  
Shell Element ◽  
Theory Of Elasticity ◽  
Shell Elements ◽  
Asme Code ◽  
Form Theory ◽  
Computation Scheme ◽  
Shell Intersections

A specialized shell-intersection finite element, which is compatible with adjoining shell elements, has been developed and has the capability of physically representing the complex three-dimensional geometry and stress state at shell intersections (Koves, 1993). The element geometry is a contoured shape that matches a wide variety of practical nozzle configurations used in ASME Code pressure vessel construction, and allows computational rigor. A closed-form theory of elasticity solution was used to compute the stress state and strain energy in the element. The concept of an energy-equivalent nodal displacement and force vector set was then developed to allow complete compatibility with adjoining shell elements and retain the analytical rigor within the element. This methodology provides a powerful and robust computation scheme that maintains the computational efficiency of shell element solutions. The shell-intersection element was then applied to the cylinder-sphere and cylinder-cylinder intersection problems.

Finite Element Analysis for a CAD of a Concrete Mixer Drum

1994 ◽  
Author(s):  
Hossam S. Badawi ◽  
Sherif A. Mourad ◽  
Sayed M. Metwalli
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Element Analysis ◽  
Shell Elements ◽  
Bending Stresses ◽  
Loading Effects ◽  
Concrete Mixer ◽  
Aided Design

Abstract For a Computer Aided Design of a concrete truck mixer, a six cubic meter concrete mixer drum is analyzed using the finite element method. The complex mixer drum structure is subjected to pressure loading resulting from the plain concrete inside the drum, in addition to its own weight. The effect of deceleration of the vehicle and the rotational motion of the drum on the reactions and stresses are also considered. Equivalent static loads are used to represent the dynamic loading effects. Three-dimensional shell elements are used to model the drum, and frame elements are used to represent a ring stiffener around the shell. Membrane forces and bending stresses are obtained for different loading conditions. Results are also compared with approximate analysis. The CAD procedure directly used the available drafting and the results were used effectively in the design of the concrete mixer drum.

Finite Element Analysis of Elliptical Chord

2013 ◽  
Vol 3 (4) ◽  
pp. 44-61
Author(s):  
K. S. Narayana ◽  
R. T. Naik ◽  
R. C. Mouli ◽  
L. V. V. Gopala Rao ◽  
R. T. Babu Naik
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Compressive Load ◽  
Dynamic Strength ◽  
Element Analysis ◽  
T Joints ◽  
Shell Elements ◽  
Tubular Joints ◽  
Plane Bending

The work presents the Finite element study of the effect of elliptical chords on the static and dynamic strength of tubular T-joints using ANSYS. Two different geometry configurations of the T-joints have been used, namely Type-1 and Type-2. An elastic analysis has been considered. The Static loading conditions used are: axial load, compressive load, In-plane bending (IPB) and Out-plane bending (OPB). The natural frequencies analysis (dynamic loading condition) has also been carried out. The geometry configurations of the T-joints have been used, vertical tubes are called brace and horizontal tubes are called chords. The joint consists of brace joined perpendicular to the circular chord. In this case the ends of the chord are held fixed. The material used is mild steel. Using ANSYS, finite element modeling and analysis of T-joint has been done under the aforementioned loading cases. It is one of the most powerful methods in use but in many cases it is an expensive analysis especially due to elastic–plastic and creep problems. Usually, three dimensional solid elements or shell elements or the combination of two types of elements are used for generating the tubular joints mesh. In tubular joints, usually the fluid induced vibrations cause the joint to fail under resonance. Therefore the natural frequencies analysis is also an important issue here. Generally the empirical results are required as guide or comparison tool for finite element investigation. It is an effective way to obtain confidence in the results derived. Shell elements have been used to model the assembled geometry. Finite element ANSYS results have been validated with the LUSAS FEA and experimental results, that is within the experimentation error limit of ten percentage.

Effect of Forming Parameters on Flexible-Bending of Three-Dimensional Tubes

2018 ◽  
Vol 937 ◽  
pp. 69-76
Author(s):  
Shuo Sun ◽  
Wen Zhi Fu ◽  
Ming Zhe Li ◽  
Yong Ping Zhou ◽  
Ying Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
Great Influence ◽  
Batch Production ◽  
Bending Effect ◽  
Forming Parameters ◽  
Bending Process ◽  
Continuous Bending ◽  
Feeding Speed

Flexible-bending is an advanced bending method, especially suitable for small batch production of tubes. The shape of forming parts is mainly related to the offset of the bend die instead of the geometry of it. Based on flexible-bending technology, 3D bending of tubes was carried out by finite element method and the effects of primary parameters on the bending results were studied. The analysis results showed that3D continuous bending of tubes can be obtained by flexible-bending process; die offset, offset speed and feeding speed of tube have a great influence on the bending effect. Bending experiments of 3D tube were carried out by flexible-bending equipment and bending radii of the forming part were measured, the results were very close to that of simulations which proved the effectiveness of simulation.

scholarly journals Analysis and Control of Twist Defects of Aluminum Profiles with Large Z-Section in Roll Bending Process

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 31 ◽  
Author(s):  
Anheng Wang ◽  
Hongqian Xue ◽  
Emin Bayraktar ◽  
Yanli Yang ◽  
Shah Saud ◽  
...  
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Element Model ◽  
Effective Control ◽  
Curvature Radius ◽  
3D Fem ◽  
Fe Method ◽  
Element Analysis ◽  
Roll Bending ◽  
Bending Process

This paper focuses on the twist defects and the control strategy in the process of four-roll bending for aluminum alloy Z-section profiles with large cross-section. A 3D finite element model (3D-FEM) of roll bending process has been developed, on the premise of the curvature radius of the profile, the particularly pronounced twist defects characteristic of 7075-O aluminum alloy Z-section profiles were studied by FE method. The simulation results showed that the effective control of the twist defects of the profile could be realized by adjusting the side roller so that the exit guide roll was higher than the entrance one (the side rolls presented an asymmetric loading mode with respect to the main rolls) and increasing the radius of upper roll. Corresponding experimental tests were carried out to verify the accuracy of the numerical analysis. The experimental results indicated that control strategies based on finite element analysis (FEA) had a significant inhibitory function on twist defects in the actual roll bending process.

Design Tools for the Performance Improvement of a 76 MW Francis Turbine Runner

2009 ◽  
Author(s):  
Jose´ Manuel Franco-Nava ◽  
Oscar Dorantes-Go´mez ◽  
Erik Rosado-Tamariz ◽  
Jose´ Manuel Ferna´ndez-Da´vila ◽  
Reynaldo Rangel-Espinosa
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Performance Improvement ◽  
Three Dimensional ◽  
Francis Turbine ◽  
Design Tools ◽  
Turbine Runner ◽  
Induced Stresses ◽  
Fluid Behaviour

Application of two mayor design tools, Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD), for the performance improvement of a 76 MW Francis turbine runner is presented. In order to improve the performance of the runner, not only a CFD based optimization for the runner but also its structural integrity evaluation was carried out. In this paper, a number of analyses included within the design tools-based runner optimization process are presented. Initially, a reference condition for the fluid behaviour through turbine components was carried out by means of the computation of fluid conditions through the spiral case and stays vanes, followed by CFD-based fluid behaviour for the wicket so as to include the flow effects induced by these components in the final CFD analysis for the runner. All CFD computations were generated within the three dimensional Navier-Stoke commercial turbomachinery oriented CFD code FINE™/Turbo from NUMECA. The whole hydraulic turbine performance was then compared against actual data from a medium-head Francis type hydro turbine (76 MW). Then, CFD-based flow induced stresses in the turbine runner were computed by using a three dimensional finite element model built within the FEA commercial code ANSYS. Appropriate boundary conditions were set in order to obtain the results due to the different type loads (pressure and centrifugal force). The FEM model was able to capture the pressure gradients on the blade surfaces obtained from the CFD results. Improvement of efficiency and power for the runner was computed by using a parametric model built within 3D CFD code integrated environment FINETM/Design3D from NUMECA which combines genetic algorithms and a trained artificial neural network. During the optimization process the artificial neural network is trained with a database of geometries and their respective CFD computations in order to determine the optimum geometry for a given objective function. The optimisation process and the trend curve of the optimization or design cycle that included 29 parameters (corresponding to the control points of runner blade primary sections) which could vary during the process is presented. Finally, the flow induced stresses of the optimized Francis turbine runner was computed so as to evaluate the final blade geometry modifications related to the efficiency and power improvement.

Lagrangian Finite Element Formulation to Axisymmetric Liquid Sloshing

2011 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuyoshi Sekine ◽  
Tomohiko Tsuchida ◽  
Katsuki Iwata
Keyword(s):  
Finite Element ◽  
Axisymmetric Problem ◽  
Time Integration ◽  
Three Dimensional ◽  
Computer Code ◽  
Element Formulation ◽  
Liquid Storage ◽  
Analysis Technique ◽  
Lagrangian Finite Element ◽  
Spurious Modes

The sloshing analysis of liquid storage tanks by the finite element method is basically categorized into two approaches, Lagrangian approach and Eulerian approach. In the Lagragian approach, the behavior of the fluid is expressed in terms of the displacements at nodal points. The advantage of the Lagragian method is that the computer code can be easily developed to modify an existing structural analysis code. The disadvantage is that some spurious modes are included in the vibration modes. The Lagrangian method is widely used in two- and three-dimensional problems. On the other hand, it has not been reported its applicability to the axisymmetric problem. This paper presents the applicability of the Lagragian method to the axisymmetric sloshing problem. The eigenvalue of an elemental stiffness matrix is analyzed in order to investigate the characteristics of the rotational stiffness to the compressibility of the fluid. As a result, this method is found to be difficult to apply to the axisymmetric problem if the equation of motion is directly solved using time integration. However, it gives the highly precise response solutions if the only sloshing modes are taken out and the modal analysis technique is used.

Finite Element Prediction of Mechanical Behaviour under Bending of Honeycomb Sandwich Panels

2014 ◽  
Vol 980 ◽  
pp. 81-85 ◽  
Author(s):  
Kaoua Sid-Ali ◽  
Mesbah Amar ◽  
Salah Boutaleb ◽  
Krimo Azouaoui
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
Element Model ◽  
Shell Elements ◽  
Numerical Characterization ◽  
Bending Load ◽  
Accurate Stress Analysis ◽  
Three Dimensional Finite Element

This paper outlines a finite element procedure for predicting the mechanical behaviour under bending of sandwich panels consisting of aluminium skins and aluminium honeycomb core. To achieve a rapid and accurate stress analysis, the sandwich panels have been modelled using shell elements for the skins and the core. Sandwich panels were modelled by a three-dimensional finite element model implemented in Abaqus/Standard. By this model the influence of the components on the behaviour of the sandwich panel under bending load was evaluated. Numerical characterization of the sandwich structure, is confronted to both experimental and homogenization technique results.

scholarly journals Finite Element Analysis of Turbulent Flows Using LES and Dynamic Subgrid-Scale Models in Complex Geometries

2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Wang Wenquan ◽  
Zhang Lixiang ◽  
Yan Yan ◽  
Guo Yakun
Keyword(s):  
Finite Element ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulent Channel Flow ◽  
Francis Turbine ◽  
Complex Geometries ◽  
Subgrid Scale ◽  
Element Analysis

An innovative computational model is presented for the large eddy simulation (LES) of multidimensional unsteady turbulent flow problems in complex geometries. The main objectives of this research are to know more about the structure of turbulent flows, to identify their three-dimensional characteristic, and to study physical effects due to complex fluid flow. The filtered Navier-Stokes equations are used to simulate large scales; however, they are supplemented by dynamic subgrid-scale (DSGS) models to simulate the energy transfer from large scales toward subgrid-scales, where this energy will be dissipated by molecular viscosity. Based on the Taylor-Galerkin schemes for the convection-diffusion problems, this model is implemented in a three-dimensional finite element code using a three-step finite element method (FEM). Turbulent channel flow and flow over a backward-facing step are considered as a benchmark for validating the methodology by comparing with the direct numerical simulation (DNS) results or experimental data. Also, qualitative and quantitative aspects of three-dimensional complex turbulent flow in a strong 3D blade passage of a Francis turbine are analyzed.

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