Ι Solving Contact Problems With Abaqus - ResearchGate
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSolving Contact Problems with AbaqusDS UK Ltd, Coventry - March 2013Stephen KingTony Richards
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSeminar AbstractContact interactions between different parts play a key role when simulatingbolted assemblies, manufacturing processes, dynamic impact events, andvarious other systems. Accurately capturing these interactions is essential forsolving many engineering problems. SIMULIA has developed state-of-the-artcontact modeling capabilities in Abaqus.Attend this seminar to learn the latest techniques and strategies for solvingdifficult contact problems with Abaqus. This seminar primarily focuses onAbaqus/Standard, with additional discussion of Abaqus/Explicit.Topics include advantages of the general contact capability, accurate contactpressures, insight on numerical methods, tips for improving convergence,recent enhancements to the implicit dynamics procedure for contact models,and proper representation of physical details associated with contact.
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙLectures Lecture 1:Introduction Lecture 2:Defining Contact in an Analysis Lecture 3:Numerical Methods for Contact Lecture 4:Contact Output and Diagnostics Tools (start)(Lunch) 12:30pm – 1.30pm Lecture 4 (cont.): Contact Output and Diagnostics Tools (finish) Lecture 5:Convergence Topics Lecture 6:Contact in Abaqus/Explicit Lecture 7:More Features
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙLegal NoticesAll Dassault Systèmes Software products described in this documentation are available onlyunder license from Dassault Systèmes or its subsidiary/subsidiaries and may be used orreproduced only in accordance with the terms of such license.The information in this document is subject to change without prior notice. Dassault Systèmesand its subsidiaries shall not be responsible for the consequences of any errors or omissionsthat may appear in this documentation.No part of this documentation may be reproduced or distributed in any form without priorwritten permission of Dassault Systèmes or its subsidiary/subsidiaries. Dassault Systèmes, 2013.Printed in the U. S. A.The 3DS logo, SIMULIA, CATIA, 3DVIA, DELMIA, ENOVIA, SolidWorks, Abaqus, Isight, andUnified FEA are trademarks or registered trademarks of Dassault Systèmes or its subsidiariesin the US and/or other countries. Other company, product, and service names may betrademarks or service marks of their respective owners.
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙIntroductionLecture 1
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙOverview General Considerations Evolution of Contact in Abaqus Contact Examples
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙGeneral Considerations What is contact? Physically, contact involves interactions between bodies Contact pressure resists penetrationFairlyintuitive Frictional stress resists sliding Electrical, thermal interactions Numerically, contact includes severe nonlinearitiesNumericallychallenging Inequality conditions result in discontinuous―stiffness‖ Gap distance: dgap 0 Frictional stress: t mp Conductance properties suddenly changewhen contact is established
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙGeneral Considerations Various classifications of contact interactions can be considered Example: slender or bulky components Bulky components: Typically many nodes in contactat one time Contact causes local deformationand shear, but it causes little bending Slender components Often relatively few nodes in contact atone time Contact causes bending Often more challenging
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙGeneral Considerations Classifications of contactinteractions: Slender or bulky components Deformable or rigid surfaces Degree of confinement andcompressibility of components Two-body contact or selfcontact Amount of relative motion(small or finite sliding) Amount of deformation Underlying element type (1st or2nd order) Interaction properties (friction,thermal, etc.) Which results are of interestand importance (e.g. contactstresses)
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 Ι„Ingredients‟ of a Contact Model Contact surfaces Surfaces over bodies that may experience contact Contact interactions Which surfaces interact with one another? Surface property assignments For example, contact thickness of a shell Contact property models Examples: pressure vs. overclosure relationship, friction coefficient, conductioncoefficients, etc. Contact formulation aspects For example, can a small-sliding formulation be used? Algorithmic contact controls Such as contact stabilization settingsMany of these aspect need not beexplicitly specified
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙGeneral Considerations Physical and numerical aspects of contact modeling: User responsible for defining physical aspects of model User and Abaqus control various numerical aspects Many details (e.g., slender or bulky classification) need not beexplicitly specified Trend toward greater automation
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact Modeling inAbaqus
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact ModelingContact elements(e.g., GAPUNI):Contact pairs:General contact:2nvh1 h d n u2 u1 0User-defined element foreach contact constraintMany pairingsfor assembliesTrends over timeModel all interactionsbetween free surfaces
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact ModelingFlat approximation of mastersurface per slave node:Master surfaceRealistic representation ofmaster surface:Master surfaceTrends over time
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact ModelingSlave surface treated ascollection of discrete points:Constraints based onintegrals over slave surface:Does not resistpenetration atmaster nodesResists penetrationat slave nodesGood resolution ofcontact over theentire interfaceTrends over time
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact Modeling Goals: improve usability, accuracy, and performance More focus by user on physical aspects Less on idiosyncrasies of numerical algorithms Broad applicability Large models (assemblies)General contact:Constraints based onintegrals over slavesurface:Realistic representation ofmaster surface:Master surfaceGood resolution ofcontact over theentire interfaceModel all interactionsbetween free surfaces
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact Modeling General contact algorithm Contact domain spans multiple bodies(both rigid and deformable) Default domain defined automaticallyvia all-inclusive, element-based surface Method geared toward models with multiplecomponents and complex topology Greater ease in defining contact model Available in Abaqus/Explicit since 6.3 Available in Abaqus/Standard since 6.8-EF
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact Modeling Transition to general contact nearly complete for Abaqus/Explicit Most Abaqus/Explicit analyses use general contact Easy to use and robust Accuracy, performance, and scalability as good or better than contact pairs Some features available only in general contact A few features available only with contact pairs
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙEvolution of Contact Modeling Transitioning to general contact in Abaqus/Standard Good feedback Easier to create model than contact pairs Similar robustness and accuracy as contact pairs Some extra contact tracking time, etc. Contact pairs are required to access specific features not yet availablewith general contact Analytical rigid surfaces Node-based surfaces or surfaces on 3-D beams Small-sliding formulation See the Abaqus Analysis User’s Manual General contact and contact pairs can be used together General contact algorithm automatically avoids processing interactionstreated with contact pairs
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙContact Examples
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙContact Examples Contact between linear elastic bodies with small relative motion Common design problems involving: Small relative motion Significant contact area Typical examples: Bearing design Hard gaskets Interference fits Fretting (surface wear) isoften a concern, requiringaccurate resolution of contactstresses and stick/slip zones
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙContact Examples Deformable-to-rigid contact Finite sliding betweensurfaces (largedisplacements) Finite strain of deformingcomponents Typical examples: Rubber seals Tire on road Pipeline on seabed Forming simulations(rigid die/mold,deformablecomponent)Example: metal forming simulationExample taken from ―Superplastic forming ofa rectangular box,‖ Section 1.3.2 in theAbaqus Example Problems Manual
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙContact Examples Finite-sliding contact betweendeformable bodies Most general category ofcontact Example: twisting blocks Press together andrelative rotation of 90
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙContact Examples Self-contact Type of 1(rigid)SURF2 Contact of a single body withitself—often involves severedeformation Sometimes adds CPUexpense and numerical difficulty General contact implementationsomewhat like self-contact ofsurface spanning multiplebodiesContour of minimum principal stressExample: compression of a rubber gasketExample taken from ―Self-contact inrubber/foam components: rubber gasket,‖Example Problem 1.1.18 in the AbaqusExample Problems Manual
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙLecture 1 Summary
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙReview of Topics Discussed in Lecture General Considerations Evolution of Contact in Abaqus Contact Examples
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining ContactLecture 2
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙOverview Defining Surfaces Defining Contact Pairs Defining General Contact Representation of Curved Surfaces
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Surfaces
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSurfaces Various Abaqus features use surfaces Contact Tie constraints Surface loads Cavity radiation Bolt pre-tensioning Various surface types exist in Abaqus Element-based (most common) Node-based Analytical rigid Eulerian (not covering coupled Eulerian-Lagrangian analysis in this seminar) Surface documentation Sections 2.3.1–2.3.6 of Abaqus Analysis User’s Manual
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSurfaces Abaqus/CAE interfaceSolid bodies Surface on solid definedby selecting appropriate regionof exterior of the part Regions can be selected individuallyor based on face angles
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSurfaces Abaqus/CAE interfaceShell-like surfaces may be: On ―positive‖ side of elements On ―negative‖ side of elements Or, on both sides
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSurfaces Element-based surfaces are composed of element faces Typically, on exposed faces of bodiesClose-up viewwith local faceID labelsLocal numbering conventionsfor brick and tet elementsExample of surfacedefined over aportion of rivet Characteristics inherited from underlying elements include: Deformable or rigid Shell/membrane thickness Some contact formulations account for this thickness Representative stiffness Influences some numerical aspects, such as penalty stiffness
Surface RestrictionsΙ www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 Ι Mostly context-specific Depend on which features use the surface Restrictions on surfaces used in contact definitions Depend on details of contact definition Documented in Abaqus Analysis User’s Manual Trend toward fewer surface restrictionsConnectedat one node Example: master surface connectivity requirementsDiscontinuousT-intersection(or 3-D faces joinedat only one node)(more than twofaces per edge)Finite-sliding,node-to-surfaceNot allowedNot owedContactformulationT-intersection Example of a general restriction on element-based surfaces Parent elements cannot be a mixture of two-dimensional,axisymmetric, and three-dimensional elements
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact Pairs
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact Pairs Features of contact pairs defined by user: What constitutes each surface Which pairs of surfaces will interact Which surface is the master and which is the slave Which surface interaction properties are relevant(e.g., friction)Potential formany pairings
Defining Contact PairsΙ www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 Ιaxis of symmetry Example: analysis of a jounce bumper Highly compressible component used in avehicle’s shock isolation system Bumper folds as it is compressed, so selfcontact is modeledFinaldeformedshape Analysis consists of two steps:Step 1 Resolve interference fitStep 2 Move the bottom plate up tocompress the bumpertopplateshaftbumperbottomplate
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact PairsTOPPLATE1 Define surfaces (using Abaqus/CAE)Double-click Surfaces tocreate a new surfaceSHAFTBUMPER-EXTModel TreeBOTPLATECreate discrete rigid part
Defining Contact PairsΙ www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙSurfaceTOPPLATE1 Define surfaces (using keywords) Automatic free surface generation on bumperelements:*SURFACE,NAME BUMPER-EXTBUMPER,SurfaceSHAFT Discrete rigid surfaces:*RIGID BODY, ELSET BOTDIE, REF NODE BOTRP*SURFACE,NAME BOTPLATEBOTDIE, SPOS*RIGID BODY, ELSET TOPDIE, REF NODE TOPRP*SURFACE, NAME TOPPLATETOPDIE, SPOSElementsetBUMPERSurfaceBUMPER-EXT*RIGID BODY, ELSET SHAFTDIE, REF NODE SHAFTRP*SURFACE, NAME SHAFTSHAFTDIE, SPOSSurfaceBOTPLATE
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact Pairs2 Define contact properties Contact property definitions are the samefor general contact and contact pairs Contact properties can include: Friction Contact damping Pressure-overclosure relationships All contact pairs use the same interactionproperty in this example:*SURFACE INTERACTION, NAME Friction*FRICTION0.05,
Defining Contact PairsΙ www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙTOPPLATE3 Define contact pairs Contact pair definition required foreach pair of surfaces that can interactSHAFT Bumper self-contact:include insidestep definition*CONTACT PAIR, INTERACTION FrictionBUMPER-EXT,BUMPER-EXTBOTPLATE
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact PairsTOPPLATE3 Define contact pairs Contact between the bumper andthe rigid bodies:SHAFT*CONTACT PAIR, INTERACTION FrictionBUMPER-EXT, TOPPLATEBUMPER-EXT, BOTPLATEBUMPER-EXT, SHAFTBUMPER-EXTBOTPLATE
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact Pairs Automatic contact pair detection in Abaqus/CAE Automatic contact detection is a fast and easy way to define contactpairs and tie constraints in a three-dimensional model Instead of individually selecting surfaces and defining the interactionsbetween them, you can instruct Abaqus/CAE to locate automatically allsurfaces in a model that are likely to interact based on initial proximity Can be used to define contact with shells, membranes, and solids Including shell offset Native or orphan mesh parts
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining Contact Pairs Automatic contact pair detection in Abaqus/CAE Example: Disk brake Tabular display of candidate contact pairs is provided Various controls over selection criteria, etc.Shortcuts; e.g.,manually add contactpairs to the group
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining General Contact
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining General Contact General contact user interface allows forconcise contact definition reflecting thephysical description of the problemTypical usage ofgeneral contact: Contact definition can be expanded incomplexity, as needed Independent specification of contactinteraction domain, contact properties,and surface attributes permitted Minimal algorithmic controls required General contact user interface is verysimilar for Abaqus/Explicit andAbaqus/Standard analysesModel all interactionsbetween free surfaces
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining General Contact Examples of differences between general contact in Abaqus/Explicitand /StandardPrimary -slave rolesBalanced master-slavePure master-slaveSecondary formulationEdge-to-edgeEdge-to-surface2-D and axisymmetricNot availableAvailableMost aspects ofcontact definitionStep-dependentModel data
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining General Contact Jounce bumper example using generalcontactaxis of symmetry Recall initial and final configurations(shown here)topplateshaftbumperbottomplate
Ι www.3ds.com Ι Dassault Systèmes Ι Confidential Information Ι 18/03/2013 ref.: 20100928MKT038 ΙDefining General Contact Contact definition1) Begin the general contact definition*Contact*Contact Inclusions, ALL EXTERI
Abaqus Example Problems Manual metal forming simulation. Ι Ι s Ι l Ι 3 Ι Contact Examples Finite-sliding contact between deformable bodies Most general category of contact Example .
ABAQUS/Explicitt * ABAQUS/Explicit Example Problems Manual, 5.8 ABAQUS ABAQUS/Standard Verification Manual, 6.2 ABAQUS/Explicit VerificationManual_6-2.pdf *ABAQUS/CAE ABAQUS ABAQUS/Standard.enc n Manual, 6.2 * ABAQUS/Explicit Benchmarking-Manual_6-2.pdf Benchmarking Manual, 6.2 * ABAQUS/CAE ABAQUS ABAQUS/Standard * ABAQUS/Explicit Examples .
ABAQUS Scripting User’s Manual 13. ABAQUS Scripting Reference Manual 14. ABAQUS Release Notes 15. ABAQUS Installation and Licensing Guide 3 1.2 Programs 1 INTRODUCTION 1.2 Programs ABAQUS/Standard and ABAQUS/Explicit are both available in the CUED teaching system comput-ers. ABAQUS/CAE is the pre-processor
Buckling, Postbuckling and Collapse Analysis 12 Composites Modeler for Abaqus/CAE 13 Co-simulation with Abaqus and Dymola 15 Crashworthiness Analysis with Abaqus 16 CZone for Abaqus 17 Electromagnetic Analysis with Abaqus 18 Element Selection in Abaqus 19 Fitness-for-Service Analysis with Abaqus 20
Use Abaqus/CAE to create complete finite element models. Use Abaqus/CAE to submit and monitor analysis jobs. Use Abaqus/CAE to view and evaluate simulation results. Solve structural analysis problems using Abaqus/Standard and Abaqus/Explicit, including the effects of material nonlinearity, large deformation and contact.
The Abaqus Student Edition consists of Abaqus/Standard, Abaqus/Explicit, and Abaqus/CAE only. Full HTML documentation is included. . Abaqus tutorials. 6 System requirements Operating system: Windows XP, Windows Vista, and Windows 7 Processor: Pentium 4 or higher
Abaqus services: Abaqus/Standard solver and Abaqus/Explicit solver. This software includes the SIMULIA Co-Simulation Engine and the foundation of all Abaqus APIs. CAA developer software for Abaqus APIs: output database (ODB) C API, user subroutines API, Abaqus Scripting Interf ac
ABAQUS/Explicit User’s Manual (Volumes I and II) 1.2 Programs ABAQUS/Standard and ABAQUS/Explicit are both available in the CUED teaching system comput-ers. ABAQUS/CAE is the pre-processor and ABAQUS/Viewer in the post processor. PATRAN is an establi
Co-simulation with Abaqus and Dymola (DYM) 15 Crashworthiness Analysis with Abaqus (CRASH) 16 CZone for Abaqus (CZA) 17 Electromagnetic Analysis with Abaqus (EMAG) 18 Element Selection in Abaqus (ELEMC) 19 Fitness-for-Service Analysis with Abaqus (FFSA) 20 Flexible
