Affect of Part Geometry on Wall Features in Rectangular Deep-Drawing Processes Using Finite Element Method

2009 ◽  
Vol 410-411 ◽  
pp. 579-585 ◽  
Author(s):  
Sutasn Thipprakmas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Complex Geometry ◽  
Thickness Distribution ◽  
Cost Effective ◽  
Bead Formation ◽  
Concave Wall ◽  
Convex Wall ◽  
Forming Defects ◽  
Element Method

High-quality stamped parts using cost-effective production technique are increasingly required, especially in parts with complex geometry wherein forming defects are easily generated. In this study, the concave and convex wall features were investigated for a stainless steel rectangular tray using the finite element method and related experiments. The concave and convex wall phenomena were theoretically clarified on the basis of stress distribution. The effects of tray geometry were also investigated. Increasing both the rectangle size and depth of tray, together with a decrease in the corner radius, resulted in an increase in concave wall generation. However, the effects of increasing the length or width of the rectangle affecting the concave wall were independent of each other. In addition, the application of a very large depth of tray resulted in a convex feature. The results showed that it is difficult to achieve a straight wall on both the ‘length’ and ‘width’ sides without the use of draw bead. The finite element simulation results showed a reasonable agreement with the experimental results, with reference to the material thickness distribution in both the cases of: absence of the draw bead formation; and presence of the draw-bead formation.

Effect of Draw Bead Height on Wall Features in Rectangular Deep-Drawing Process Using Finite Element Method

2011 ◽  
Vol 264-265 ◽  
pp. 1580-1585 ◽  
Author(s):  
Sutasn Thipprakmas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tensile Stress ◽  
Fem Simulation ◽  
Bead Geometry ◽  
Concave Wall ◽  
Convex Wall ◽  
Simulation Results ◽  
Bead Height ◽  
Element Method

Concave/convex wall features are usually generated in the deep-drawn parts with complicated geometry, especially the difficult-to-deep draw materials. The application of the draw bead could reduce the concave/convex wall features. However, it is difficult to determine the suitable draw bead geometry and its position to obtain a straight wall. In this study, the effects of draw bead height were investigated using the finite element method (FEM) and experiments. The application of the draw bead and the effects of its height on the concave/convex wall features could be theoretically clarified on the basis of principal stress distribution. The application of draw bead led to the decrease in tensile stress in the direction of punch movement and also increased in the tensile stress distributed to the corner zone; therefore, the concave wall feature decreased. In addition, this feature decreased as the draw bead height increased. However, the application of a very large draw bead height resulted in a convex feature. The FEM simulation results were validated by experiments in the following two cases, i.e., without and with draw bead formations. With reference to the material thickness distribution, the FEM simulation results showed a good agreement with experimental results.

Numerical implementation of finite-element method of control volume using irregular mesh

2010 ◽  
Vol 7 ◽  
pp. 98-108
Author(s):  
Yu.A. Gafarova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Delaunay Triangulation ◽  
Complex Geometry ◽  
Control Volume ◽  
Test Case ◽  
The Finite Element Method ◽  
Irregular Mesh ◽  
Discrete Analogues ◽  
Element Method

To solve problems with complex geometry it is considered the possibility of application of irregular mesh and the use of various numerical methods using them. Discrete analogues of the Beltrami-Mitchell equations are obtained by the control volume method using the rectangular grid and the finite element method of control volume using the Delaunay triangulation. The efficiency of using the Delaunay triangulation, Voronoi diagrams and the finite element method of control volume in a test case is demonstrated.

A Coupled SBFEM-FEM Approach for Evaluating Stress Intensity Factors

2013 ◽  
Vol 353-356 ◽  
pp. 3369-3377 ◽  
Author(s):  
Ming Guang Shi ◽  
Chong Ming Song ◽  
Hong Zhong ◽  
Yan Jie Xu ◽  
Chu Han Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Geometry ◽  
Stress Singularity ◽  
Intensity Factors ◽  
Finite Element Software ◽  
Scaled Boundary Finite Element ◽  
Element Method

A coupled method between the Scaled Boundary Finite Element Method (SBFEM) and Finite Element Method (FEM) for evaluating the Stress Intensity Factors (SIFs) is presented and achieved on the platform of the commercial finite element software ABAQUS by using Python as the programming language. Automatic transformation of the finite elements around a singular point to a scaled boundary finite element subdomain is realized. This method combines the high accuracy of the SBFEM in computing the SIFs with the ability to handle material nonlinearity as well as powerful mesh generation and post processing ability of commercial FEM software. The validity and accuracy of the method is verified by analysis of several benchmark problems. The coupled algorithm shows a good converging performance, and with minimum additional treatment can be able to handle more problems that cannot be solved by either SBFEM or FEM itself. For fracture problems, it proposes an efficient way to represent stress singularity for problems with complex geometry, loading condition or certain nonlinearity.

A numerical approach based on finite element method for the wrinkling analysis of dielectric elastomer membranes

2021 ◽  
pp. 1-37
Author(s):  
Guoyong Mao ◽  
Wei Hong ◽  
Martin Kaltenbrunner ◽  
Shaoxing Qu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thickness Distribution ◽  
Numerical Approach ◽  
Dielectric Elastomer ◽  
Equivalent Model ◽  
Maxwell Stress ◽  
Buckling Mode ◽  
Post Buckling ◽  
Element Method

Abstract Dielectric elastomer (DE) actuators are deformable capacitors capable of a muscle-like actuation when charged. When subjected to voltage, DE membranes coated with compliant electrodes may form wrinkles due to the Maxwell stress. Here, we develop a numerical approach based on the finite element method (FEM) to predict the morphology of wrinkled DE membranes mounted on a rigid frame. The approach includes two steps, I) pre-buckling and II) post-buckling. In step I, the first buckling mode of the DE membrane is investigated by substituting the Maxwell stress with thermal stress in the built-in function of the FEM platform SIMULIA Abaqus. In step II, we use this first buckling mode as an artificial geometric imperfection to conduct the post-buckling analysis. For this purpose, we develop an equivalent model to simulate the mechanical behavior of DEs. Based on our approach, the thickness distribution and the thinnest site of the wrinkled DE membranes subjected to voltage are investigated. The simulations reveal that the crests/troughs of the wrinkles are the thinnest sites around the center of the membrane and corroborate these findings experimentally. Finally, we successfully predict the wrinkles of DE membranes mounted on an isosceles right triangle frame with various sizes of wrinkles generated simultaneously. These results shed light on the fundamental understanding of wrinkled dielectric elastomers but may also trigger new applications such as programmable wrinkles for optical devices or their prevention in DE actuators.

Development of SFEM-Pre: A Novel Preprocessor for Model Creation for the Smoothed Finite Element Method

2019 ◽  
Vol 17 (02) ◽  
pp. 1845002 ◽  
Author(s):  
J. F. Zhang ◽  
R. P. Niu ◽  
Y. F. Zhang ◽  
C. Q. Wang ◽  
M. Li ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Efficient Computation ◽  
Practical Engineering ◽  
Smoothed Finite Element Method ◽  
2D And 3D ◽  
First Time ◽  
Element Method

Smoothed finite element method (S-FEM) is a new general numerical method which has been applied to solve various practical engineering problems. It combines standard finite element method (FEM) and meshfree techniques based on the weaken-weak (W2) formulation. This project, for the first time, develops a preprocessor software package SFEM-Pre for creating types of two-dimensional (2D) and three-dimensional (3D) S-FEM models following strictly the S-FEM theory. Because the software architecture of our 3D processor is the same as our 2D preprocessor, we will mainly introduce the 2D preprocessor in terms of software design for easier description, but the examples will include both 2D and 3D cases to fully demonstrate and validate the whole preprocessor of S-FEM. Our 2D preprocessor package is equipped with a graphical user interface (GUI) for easy use, and with a connectivity database for efficient computation. Schemes are developed for not only automatically meshes the problem domains using our GUI, but also accepts various geometry files made available from some existing commercial software packages, such as ABAQUS®and HyperMesh®. In order to improve the efficiency of our preprocessor, a parallel triangulation mesh generator has also been developed based on the advancing front technique (AFT) to create triangular meshes for complex geometry, and at the same time to create six types of connectivity needed for various S-FEM models. In addition, a database is implemented in our code to record all these connectivity to avoid duplicated calculation. Finally, intensive numerical experiments are conducted to validate the efficiency, accuracy and stability of our preprocessor codes. It is shown that with our preprocessor, an S-FEM can be created automatically without much human intervention for geometry of arbitrary complexity.

An Investigation of the Shell Nosing Process by the Finite-Element Method. Part 1: Nosing at Room Temperature (Cold Nosing)

1982 ◽  
Vol 104 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Ming-Ching Tang ◽  
Shiro Kobayashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Room Temperature ◽  
Moving Boundary ◽  
Thickness Distribution ◽  
The Finite Element Method ◽  
Forming Process ◽  
Finite Element Program ◽  
Strain Rate Effects ◽  
Element Method

The metal-forming process of shell nosing at room temperature was analyzed by the finite-element method. The strain-rate effects on materials properties were included in the analysis. In cold nosing simulations, the nine-node quadrilateral elements with quadratic velocity distribution were used for the workpiece. The treatment of a moving boundary in the analysis of nosing is discussed and successfully implemented in the finite-element program. FEM simulations of 105-mm dia. shells of AISI 1018 steel and aluminum 2024 were performed and solutions were obtained in terms of load-displacement curves, thickness distribution, elongation, and strain distributions. Comparisons with experimental data show very good agreement.

A Numerical Solution for Vibration Analysis of the Stiffened Variable-Thickness Conical Shells

2015 ◽  
Vol 757 ◽  
pp. 121-125
Author(s):  
Wei Ning ◽  
Feng Sheng Peng ◽  
Nan Wang ◽  
Dong Sheng Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Variable Thickness ◽  
Conical Shell ◽  
Thickness Distribution ◽  
Ritz Method ◽  
Free Vibrations ◽  
Conical Shells ◽  
Linear Eigenvalue Problem ◽  
Element Method

The free vibrations of the stiffened hollow conical shells with different variable thickness distribution modes are investigated in detail in the context of Donnel-Mushtari conical shell theory. Two sets of boundary conditions have been considered. The algebraic energy equations of the conical shell and the stiffeners are established separately. The Rayleigh-Ritz method is used to equate maximum strain energy to maximum kinetic energy which leads to a standard linear eigenvalue problem. Numerical results are presented graphically for different geometric parameters. The parametric study reveals the characteristic behavior which is useful in selecting the shell thickness distribution modes and the stiffener type. The comparison between the present results and those of finite element method shows that the present results agree well with those of finite element method.

Level Set Based Finite Element Method of Bubble-in-Liquid Simulation

2005 ◽  
Author(s):  
Hyoung G. Choi ◽  
S. W. Kang ◽  
J. Y. Yoo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Level Set ◽  
Liquid Flow ◽  
Unstructured Mesh ◽  
Flow Problem ◽  
Complex Geometry ◽  
Two Phase ◽  
Volume Method ◽  
Element Method

As far as the author knows, few papers have been reported for the level set simulation of a two-phase (bubble-in-liquid or liquid droplet-in-gas) flow based on unstructured background mesh. Almost all existing studies are based on structured mesh using finite difference or finite volume method as spatial discretization. Therefore, the application of existing various level set methods based on structured mesh to a bubble-in-liquid flow problem in a complex geometry is not straightforward. In the present study, a level set based two-phase flow code has been developed using finite element discretization, which can be utilized for the analysis of a bubble-in-liquid flow problem in a complex geometry. Since the finite element method has been employed for the spatial discretization of governing equations, unstructured mesh can be naturally adopted for the level set simulation of a bubble-in-liquid flow without an additional load for the code development except that solution methods of the hyperbolic type redistancing and advection equations of the level set function should be devised in order to give a bounded solution on unstructured mesh. In this study, some issues of the level set simulation based on finite element method for a bubble-in-liquid flow problem are discussed including the discretization of the hyperbolic type equations using SUPG type formulation and a three-dimensional benchmark problem of a bubble-in-liquid motion have been solved and compared with the existing results. It has been shown that the present bubble-in-liquid simulation method based on FEM gives a satisfactory solution with the level set method alone while the other researches based on finite difference/volume method use a combined level-set/volume-of-fluid method (CLSVOF) or solve another equation of the volume conservation constraint in order to circumvent a volume loss/gain problem in a level set simulation.

scholarly journals The Finite Element Method Applied to the Magnetostatic and Magnetodynamic Problems

2020 ◽  
Author(s):  
Dang Quoc Vuong ◽  
Bui Minh Dinh
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Fields ◽  
Complex Geometry ◽  
Analytic Method ◽  
The Finite Element Method ◽  
Electromagnetic Problems ◽  
Common Technique ◽  
The Finite Difference Method ◽  
Element Method

Modelling of realistic electromagnetic problems is presented by partial differential equations (FDEs) that link the magnetic and electric fields and their sources. Thus, the direct application of the analytic method to realistic electromagnetic problems is challenging, especially when modeling structures with complex geometry and/or magnetic parts. In order to overcome this drawback, there are a lot of numerical techniques available (e.g. the finite element method or the finite difference method) for the resolution of these PDEs. Amongst these methods, the finite element method has become the most common technique for magnetostatic and magnetodynamic problems.

Numerical Simulation of Ship Collision With Gravity Base Foundations of Offshore Wind Turbines

2013 ◽  
Author(s):  
Thorben Hamann ◽  
Torben Pichler ◽  
Jürgen Grabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cost Effective ◽  
Offshore Structures ◽  
Contact Forces ◽  
Offshore Wind ◽  
The Finite Element Method ◽  
Effective Manner ◽  
Ship Collision ◽  
Element Method

For the installation of offshore foundations several countries (e.g. Germany) require a proof of averting environmental disasters in case of ship collision. The aim is to prevent possible discharge of supplies or even loss of the vessel. Especially for gravity base foundations this load case is problematic due to their larger stiffness and mass compared to monopiles, tripods or jacket foundations. The finite element method provides a powerful tool to predict the collision behaviour in a realistic way taking into account the complex interaction between vessel, foundation and soil. The collision between a fully loaded single hull tanker and a gravity base foundation is subject of numerical analysis. The calculated contact forces between vessel and foundation are compared to a simplified calculation approach. For evaluation of the foundation deformations and areas of failure of the vessel are investigated. The influence of the water depth, the diameter of the foundation and an embedment in the seabed are determined in a parametric study. It can be shown that the finite element method is a suitable approach for investigation of the collision behaviour of offshore structures. The design of gravity base foundations can be optimized with respect to ship collision in a fast and cost-effective manner using this method.

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