Comparative Study of Finite Element

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Laboratory for Manufacturing

AutomationConsortium on Deburring and Edge Finishing

(University of California, Berkeley)

Year Paper gardner

Comparative Study of Finite Element

Simulation Software

Joel D. Gardner Athulan VijayaraghavanUC Berkeley UC Berkeley

David A. DornfeldUniversity of California, Berkeley

This paper is p osted at the eScholarship Repository, University of California.

http://repositories.cdlib.org/lma/codef/gardner 05 01

Copyright c2005 by the authors.


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COMPARATIVE STUDY OF FINITE ELEMENT SIMULATIONSOFTWARE

Athulan [email protected]

Joel D. [email protected]

Sponsored byNSF Grant DMI-0300549 GOALI: Development of Comprehensive

Drilling Simulation Tool

ABSTRACT

The choice of finite element software formachining analysis is an important factor indetermining the quality and scope of analysisthat can be performed. In this report, acomparative study is presented on threecommercially available finite element analysissoftware packages detailing their applicabilityfor performing machining simulations,specifically to study burr formation. The threepackages presented are Deform, AdvantEdgeand Abaqus. Each software package is

discussed first and its advantages anddisadvantages are presented. Then, thepackages are compared and the suitablepackage for different scenarios is suggested.

Keywords: Finite element method, machining,software.

INTRODUCTION

The finite element (FE) method has been avery popular tool in analyzing machining

operations, especially to study edgephenomenon such as burr formation. FEformulations are easier to apply than analyticalmethods which tend to be cumbersome andinvolve the tedious applications of boundaryconditions (Klocke, 2002). Also, burr formationis an elastic-plastic problem with large scalematerial deformation, and it is tedious to setupanalytical equations to model this (Min, 2001).

Currently, all the finite element formulationsdone by the LMA involve the use of some kindof a commercial FE package. Indeed, giventhe complexity of the finite element method,other options, such as customized solvers, are

very time consuming. The choice of packageis very important for both the type of analysisthat can be performed as well as the quality ofthe results. This is because different packageshave different capabilities and it is critical toselect the package with the appropriatefeature set. Furthermore, the assumptions andsolver techniques used in the package havefar reaching consequences in the resultsobtained from the simulations.

This report discusses the use of three softwarepackages: Abaqus, Deform and AdvantEdge.

First, the software packages are describedand their advantages and disadvantages aredetailed. They are then compared and asuggestion is made for which type of packageis most suitable for which type of analysis. Theultimate use of these software packages is forstudy of the following:

Burr formation in curved-surface drillingand drilling of intersecting holes

Machining of composite materials Burr formation in drilling of multilayer

materials

DEFORM

Background

Deform, short for Design Environment forForming, is a product of Scientific FormingTechnologies Company (SFTC) and is acommercially available FEM solver that can beapplied to several manufacturing processes.Deform's original area of specialty was inmetal forming operations like forging. It has

since expanded to include modules thatsupport machining operations.


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Advantages

Deforms machining modules can be used toquickly set up standard machining processeslike turning, milling and drilling. The user has

to supply the workpiece and tool geometry aswell as the process parameters. The solverthen uses a standard solver configuration andfinds the solution. Alternatively, the user hasthe ability to adjust solver parameters likemesh-size, nodal boundary conditions, andtool-workpiece interaction properties, forexample. Given that many of theseparameters remain constant from onesimulation to the next, the pre-programmedmodules can work very effectively. However,for detailed research and analysis, the highlevel of control is desirable. Fortunately,

Deform can accommodate both modes ofsimulation.

Deform also has an extensive material librarycontaining models of several commonmaterials and alloys. The program also hasthe capability of defining new materials basedon stress/strain data and other key materialproperties. This contributes to the usability ofthe program to simulate actual processconditions and increases its applicability.

Deform uses adaptive meshing controls to

accommodate high workpiece deformationsthat are very common in machining. Thisensures the accuracy of the solution as well asensuring that an optimal number of elementsare used overall. That is, more elements areused where strain rates are high and there islarge deformation and fewer elements areused little deformation is takes place.

Disadvantages

Deform's drilling module is still in a betaversion and there are a few deficiencies that

are being addressed. The workpiece tends todemand more and more elements as thesimulation progresses, which causes thesimulation to run slower with time. In addition,the simulation will stop periodically and themesh size needs to be adjusted by the user.There are several fine points whichaccompany the learning curve for Deform, butthe learning process is not tedious.

Summary

Overall, Deform is a very useful program in

simulating metal cutting processes. It is verydiverse in the types of simulations it can run

and the user has a good amount of controlover the process conditions. Both thepreprogrammed module and the high controlinterface are straightforward and logical.

Although there are still some bugs that need tobe worked out, the program is still very

functional and it is very valuable in the area ofmetal cutting FEM simulations.

ADVANTEDGE

ThirdWave Systems AdvantEdge is amachining specific FEM package. It has pre-programmed modules for both 2D and 3Dmachining operations including turning andmilling. AdvantEdge also comes with aworkpiece modeler as well as a materialproperty library.

Advantages

As AdvantEdge has been explicitly written withmachining operations in mind, its solvers havebeen optimized specifically for metal-cuttingprocesses. Also, the software has a very user-friendly interface with simple input screens tosupply the tool and workpiece geometries aswell as the process parameters. AdvantEdgehas a built-in editor for simple tool andworkpiece geometries and allows for theimport of more complex geometries.

AdvantEdge also has a very extensivematerial library with models of manyengineering metals and alloys, includingseveral aerospace alloys. Specifying newmaterials is relatively simple and the user hasthe capability to enter the properties of thematerial using different models.

The program also uses adaptive meshing tohandle increase the accuracy of the solution inthe areas of high deformation and allows areasonable degree of flexibility in the meshing

controls.

Disadvantages

AdvantEdge does not give the user muchflexibility in configuring the controls of thesolver. While this may be preferable in somecases, this means that the user is restricted tothe preset controls of the software. Thesoftware also has no support for drillingoperations. A beta version with thisfunctionality has been announced, however.

Also, while the software has built-in material

models of aerospace alloys, it does not haveany support for aerospace composites.


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Scenarios

If a quick, easy to setup machining simulationis needed, then the preferable softwarepackages would be Deform and AdvantEdge.These packages allow quick setup of

simulations and have built in modules tospecify material properties, tool and workpiecegeometries and process parameters. Betweenthese two packages, Deform offers morecontrol over the simulation process while

AdvantEdge is easier to setup.

In order to perform detailed simulations wheredifferent solver mechanisms need to be usedand precise control is needed over the meshand the boundary conditions, then thepreferable software package is Abaqus.

ACKNOWLEDGEMENTS

The authors thank Chris Fischer of SFTC,Troy Marusich of Third Wave Systems andNuno Rebello of Abaqus for providing the LMAwith software and assistance. The authorsalso thank the members of the Consortium onDeburring and Edge Finishing (CODEF) fortheir discussions, feedback and financialsupport for this work. The National ScienceFoundation is gratefully acknowledged forfunding this research under grant DMI-

0300549 GOALI: Development ofComprehensive Drilling Simulation Tool.

REFERENCES

Choi, J., Min, S., Dornfeld, D. A., Alam, M.,Tzong, T. (2003), Modeling of Inter-layer GapFormation in Drilling of a MultilayeredMaterial, CIRP International Workshop onModeling of Machining Operations, McMasterUniversity, May 20

th.

Klocke, F., Beck, T., Hoppe, S., Krieg, T.,Muller, N., Nothe, T., Raedt, H.-W., Sweeny,K. (2002), Examples of FEM Application inManufacturing Technology, Journal ofMaterial Processing and Technology, 120, pp.450-457.

Min, S., Dornfeld, D., Kim, J., Shyu, B. (2001),Finite Element Modeling of Burr Formation inMetal Cutting, Machining Science andTechnology, 5/2, pp. 307-322.

Park, B., 1996, Modeling of Burr Formation

Processes in Metal Cutting, Ph.D.Dissertation, U. C. Berkeley.

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Comparative Study of Finite Element