Finite Element Modelling of contact phenomena in structural analysis ??Finite Element Modelling of contact phenomena in structural analysis Albert Konter Netherlands Institute for

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  • NIMR College NAFEMS Contact Workshop: 1

    Netherlands Institute for Metals Research

    Finite Element Modelling of contact phenomena in structural analysis

    Albert Konter

    Netherlands Institutefor Metals Research

  • NIMR College NAFEMS Contact Workshop: NIMR 2

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    www.nimr.nl

  • NIMR College NAFEMS Contact Workshop: NIMR 3

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    Welding

    www.nimr.nlSysweld

  • NIMR College NAFEMS Contact Workshop: NIMR 4

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    Steel production

    www.nimr.nlMSC.Marc

  • NIMR College NAFEMS Contact Workshop: NIMR 5

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    Aluminium production

    www.nimr.nlMSC.Marc

  • NIMR College NAFEMS Contact Workshop: NIMR 6

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    Fundamentals of forming

    cutting process

    www.nimr.nl

  • NIMR College NAFEMS Contact Workshop: NIMR 7

    Netherlands Institute for Metals Research

    Netherlands Institute for Metals Research

    A Benchmark on Hydro Mechanical forming shows that modelling contact/friction is still a critical issue

    DiekA

    Sheet metal forming

  • NIMR College NAFEMS Contact Workshop: Contents 8

    Netherlands Institute for Metals Research

    Contents

    Overview of contact analysis using FE Contact comparisons

    MSC.MARC & Abaqus

    Seminar themes FE contact benchmarks difficulties by FE users in modeling contact problems current limitations of commercial FE codes desirable contact features not currently offered by FE software need for further research in application of contact problems

    Concluding remarks

  • NIMR College NAFEMS Contact Workshop: Some examples 9

    Netherlands Institute for Metals Research

    Shock absorber

    Rubber-steel assembly

    Self contact rubber

    Rigid steel insert

    Large deformations

  • NIMR College NAFEMS Contact Workshop: Some examples 10

    Netherlands Institute for Metals Research

    Bio medical

    experimentFE simulation

  • NIMR College NAFEMS Contact Workshop: Some examples 11

    Netherlands Institute for Metals Research

    Sheet metal forming

    deformable body blank

    rigid bodies blank holder

    binder punch die

    constraints friction drawbeads Optris

  • NIMR College NAFEMS Contact Workshop: Some examples 12

    Netherlands Institute for Metals Research

    Bulk metal forming

    thermal contact

    rigid tools

    remeshing

    contact redefined during analysis

  • NIMR College NAFEMS Contact Workshop: Some examples 13

    Netherlands Institute for Metals Research

    Ship collision experiment

    Royal Schelde

  • NIMR College NAFEMS Contact Workshop: Contact methodology 14

    Netherlands Institute for Metals Research

    Information for a contact analysis

    what are the various contact bodies? can some bodies be considered as rigid? what is the outline of the body?

    surface description nodes and segments

    are the (undeformed) boundary contours curved or initially straight?

    which bodies can contact each other during the analysis?

    what are contact properties at the interface normal contact tangential contact

  • NIMR College NAFEMS Contact Workshop: Contact methodology 15

    Netherlands Institute for Metals Research

    Information for a contact analysis (continued)

    Can a body get in contact with itself ? Is there an initial overlap (shrink fit simulations) or a

    discrete clearance? When are nodes considered to be in contact?

    tolerance values If contact, how is this modelled?

    node to node node to segment segment to segment

    When are nodes considered to separate?

  • NIMR College NAFEMS Contact Workshop: Contact methodology 16

    Netherlands Institute for Metals Research

    FEM contact phenomena

    Contact description special action needed

    non-linear springs contact elements contact procedures

    method of contact node to curve/surface node to segment segment to segment

    111 FuK =222 FuK =

    =

    2

    1

    2

    1

    2

    1

    00

    FF

    uu

    KK

    careful with rigid body modes if no contact

  • NIMR College NAFEMS Contact Workshop: Approaches 17

    Netherlands Institute for Metals Research

    Approaches (1)

    node to node contactnr

    Only if limited sliding contact mesh generation requires opposite nodes specify normal direction

    from position of nodes manually if nodes initially very close

  • NIMR College NAFEMS Contact Workshop: Approaches 18

    Netherlands Institute for Metals Research

    Simplified beam model

    collapse element

    gap element springs mass distributions

    Question:

    How is characteristic of collapse element determined?

    F

    u

  • NIMR College NAFEMS Contact Workshop: Approaches 19

    Netherlands Institute for Metals Research

    Approaches (2)

    node to segment contactnr

    nrnr

    Frequently applied line or surface segment allows unequal number of elements at both sides of contact surface problem with normal definition near corners nodes sliding to a next segment: additional action needed

  • NIMR College NAFEMS Contact Workshop: Approaches 20

    Netherlands Institute for Metals Research

    Example node to segment contact

    top rigid surface is load controlled

  • NIMR College NAFEMS Contact Workshop: Approaches 21

    Netherlands Institute for Metals Research

    Example node to segment contact

    mesh test section

    Royal Schelde

    The Netherlands

  • NIMR College NAFEMS Contact Workshop: Approaches 22

    Netherlands Institute for Metals Research

    Motion bulb: displacement controlledMotion bulb: displacement controlled

  • NIMR College NAFEMS Contact Workshop: Approaches 23

    Netherlands Institute for Metals Research

    Approaches (3)

    segment to segment contactnr

    Beam to beam contact problems useful if large amount of sliding present specify normal direction cross-sections can be accounted for in

    closure distance determination

  • NIMR College NAFEMS Contact Workshop: Approaches 24

    Netherlands Institute for Metals Research

    Beam contact

  • NIMR College NAFEMS Contact Workshop: Approaches 25

    Netherlands Institute for Metals Research

    Beam contact

    frictional forces

  • NIMR College NAFEMS Contact Workshop: Contents 26

    Netherlands Institute for Metals Research

    Surface to surface contact

    surface penetrates

    contact satisfied for node with segment

  • NIMR College NAFEMS Contact Workshop: Contact methodology 27

    Netherlands Institute for Metals Research

    Normal contact methodology

    visual inspection incremental displacements occurring during analysis of problem defined without contact methodology and adaptation of the boundary conditions

    non-linear springs

    contact elements Lagrange multipliers Penalty function

    contact procedures

    not practical

    limited application

    academic literature

    often in finite element codes

    MARC & Abaqus

  • NIMR College NAFEMS Contact Workshop: Contact methodology 28

    Netherlands Institute for Metals Research

    Simple contact example

    0.2

    u = 0.3

    ru

    Contact:

    stiffnessustiffnessnou

    r

    r

    2.02.0

    == rrr

    Axr

    lxr

  • NIMR College NAFEMS Contact Workshop: Contact methodology 37

    Netherlands Institute for Metals Research

    Lagrangian multipliers

    add constraint equation through Lagrangian multiplier accurate satisfaction of contact at the cost of extra degrees of freedom

    often direct determination of contact stresses/forces potentially zeros on the diagonal matrix

    Introduction of gap or contact elements

    node to node contact

    node to segment contact

  • NIMR College NAFEMS Contact Workshop: Contact methodology 38

    Netherlands Institute for Metals Research

    Compression of circular segment

    closure distance is function of position

  • NIMR College NAFEMS Contact Workshop: Contact methodology 39

    Netherlands Institute for Metals Research

    Deformable rigid contact

    normal direction to surface for each node different

  • NIMR College NAFEMS Contact Workshop: Contact methodology 40

    Netherlands Institute for Metals Research

    Penalty stiffness

    contact element with same technology as non-linear spring no extra degrees of freedom user defined or default penalty stiffness

    high stiffness: convergence problemssometimes overcome through damping mechanisms

    low stiffness: nodal penetration

    forgiving for bad contact detection

  • NIMR College NAFEMS Contact Workshop: Contact methodology 41

    Netherlands Institute for Metals Research

    Contact elements or contact procedures

    Aspects node to node contact

    slid

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