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a7-pipe-whip-kw

By Alvin Garcia,2014-10-05 07:13
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a7-pipe-whip-kw

    Answers 7

    Contact with Abaqus/Explicit

    Keywords Version

    Question W71: Why is density required in the material model definition? Can

    you comment on the units of density used in this problem?

    Answer: All Abaqus/Explicit analyses require a density value because

    Abaqus/Explicit solves for dynamic equilibrium (i.e., inertia

    effects are considered). The units for all material parameters

    must be consistent; in this problem the English system is used

    with pounds and inches as the units for force and length, 24respectively. Thus, the consistent unit for density is lb-sec/in.

    The options required to complete the material model definition

    are:

    *material, name=steel

    *density

     7.324e-4,

    *elastic

     3e+07, 0.3

    *plastic

     45000.,0.

    Question W72: Why are only three integration points used through the

    thickness?

    Answer: Three section points are used to reduce the run time of the job.

    The options required to complete the section definitions are:

    *shell section, elset=pipe-impacting,

    material=steel, section integration=gauss

    0.432, 3

    *shell section, elset=pipe-fixed,

    material=steel, section integration =gauss

    0.432, 3

    ? Dassault Systèmes, 2008 Introduction to Abaqus/Standard and Abaqus/Explicit

    WA7.2

    Question W73: In order to drive both the translations and rotations of the pipe

    edge nodes, what type of node set needs to be used in the rigid

    body constraint?

    Answer: A tie node set needs to be used.

    The option required to define the rigid body constraint is:

    *rigid body, ref node=refPt, tie nset=edge

    Question W74: Should you add the contact definition to the model data or the

    history data?

    Answer: General contact definitions can be part of either the model

    data or the history data. The surface interaction properties are

    model data when used with general contact.

    The (model data) options required to complete the contact

    definition are:

    *contact

    *contact inclusions, all exterior

    *contact property assignment

     , , fric

    *surface interaction, name=fric

    *friction

     0.2,

    Question W75: How can you use the coordinates of the reference point to

    define the axis of rotation?

    Answer: The axis passes through the reference point and is parallel to

    the Z-direction. Thus, define the axis using two points. Each of

    the “axis” points must have the same X- and Y-coordinates as

    the reference point; the values of the Z-coordinates of the

    “axis” points will dictate the sense of positive rotation.

    For example:

    *initial conditions, type=rotating velocity

    pipe-impacting, 75., 0., 0., 0.,

    25., 6.932, 0., 25., 6.932, 1.,

    The second data line defines the axis of rotation.

    Question W76: Are the boundary conditions part of the model data or the

    history data in an Abaqus/Explicit analysis?

    Answer: As with Abaqus/Standard, fixed boundary conditions can be

    defined as either model or history data. Named boundary

    conditions improve the readability of your input file and

    ? Dassault Systèmes, 2008 Introduction to Abaqus/Standard and Abaqus/Explicit

    WA7.3

    provide a shortcut to defining commonly encountered support conditions.

    The options required to define the boundary conditions, step, and output are:

    *dynamic, explicit

    , 0.015

    **

    *boundary

    zsymm, zsymm

    fixed, encastre

    refPt, pinned

    *output, field, variable=preselect,

    number intervals=12

    *output, history, time interval=0.00015

    *node output, nset=refpt

    rf1, rf2, rf3

    *output, history, variable=preselect

    Question W77: What do the energy history plots indicate?

    Answer: Near the end of the simulation, the impacting pipe is beginning to rebound, having dissipated the majority of its kinetic energy by inelastic deformation in the crushed zone.

    ? Dassault Systèmes, 2008 Introduction to Abaqus/Standard and Abaqus/Explicit

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