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Two overlapping plates are connected using three spotwelds. The plates are pulled apart until the spot welds reach the defined failure condition.

Introduction

*CONSTRAINED_SPOTWELD
Spot Weld Secures Two Plates
LS-DYNA Manual Section: *CONSTRAINED_SPOTWELD

Additional Sections:
*BOUNDARY_PRESCRIBED_MOTION_SET
*DATABASE_CROSS_SECTION_PLANE
*DATABASE_CROSS_SECTION_SET

Example: Spot Weld Secures Two Plates

Filename: constrained.spotweld.plates.k

Description:
Two overlapping plates are connected using three spotwelds. The plates are
pulled apart until the spot welds reach the defined failure condition.

Model:
The two plates measure 80*40*1 mm3 and are defined with S/R Hughes-Liu
shell elements to control hourglassing. The location of the spotwelds
connecting the two plates is in the center of the overlapping section.
One end of the plate has fixed constraints and the other end of the other plate
has linearly increasing displacement.

Input:
The nodal point cards contain the boundary conditions at one end of the plate
(*NODES). *BOUNDARY_PRESCRIBED_MOTION_SET defines the nodal motion of the end
of the other plate. Massless beams simulate the connection between the plates
at three locations (*CONSTRAINED_SPOTWELD). The definitions include failure
as a function of the axial and shear force.

The ASCII file swforc contains the axial and shear forces on the spotweld
(*DATABASE_SWFORC). A cross section is defined through each of the plates
using two different techniques (*DATABASE_CROSS_SECTION_PLANE,
*DATABASE_CROSS_SECTION_SET). Forces and moments through the cross sections
are stored in the ASCII file secforc (*DATABASE_SECFORC).

Keywords

*BOUNDARY_PRESCRIBED_MOTION_SET
*CONSTRAINED_SPOTWELD
*CONTACT_AUTOMATIC_SINGLE_SURFACE
*CONTROL_ENERGY
*CONTROL_OUTPUT
*CONTROL_SHELL
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_CROSS_SECTION_PLANE
*DATABASE_CROSS_SECTION_SET
*DATABASE_GLSTAT
*DATABASE_HISTORY_NODE
*DATABASE_MATSUM
*DATABASE_NODAL_FORCE_GROUP
*DATABASE_NODFOR
*DATABASE_NODOUT
*DATABASE_SECFORC
*DATABASE_SWFORC
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*KEYWORD
*MAT_PLASTIC_KINEMATIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SHELL_LIST
*TITLE

Reduced Input

  *KEYWORD
  *TITLE
  Two Spotwelded Plates Pulled Apart with a Specified Velocity
  $
  $  LSTC Example
  $
  $  Last Modified: September 4, 1997
  $
  $  Model initially changed from old lstc example to partially reflect paper
  $  by Matzenmiller, et al (ls-dyna conf 9/94) -  Major differences include the
  $  material and element formulation, units, and velocity loading.
  $  
  $
  $  Units: mm, kg, ms, kN, GPa, kN-mm
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Control Ouput
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  *CONTROL_TERMINATION
  $   endtim    endcyc     dtmin    endneg    endmas
        8.00
  $
  *CONTROL_ENERGY
  $     hgen      rwen    slnten     rylen
           2         2         2
  $
  *CONTROL_OUTPUT
  $    npopt    neecho    nrefup    iaccop     opifs    ipnint    ikedit
           1         3
  $
  *CONTROL_SHELL
  $   wrpang    itrist     irnxx    istupd    theory       bwc     miter
                                         1
  $
  $
  *DATABASE_BINARY_D3PLOT
  $       dt      lcdt
         0.2
  $
  *DATABASE_BINARY_D3THDT
  $       dt      lcdt
       99999
  $
  *DATABASE_GLSTAT
  $       dt
       0.010
  $
  *DATABASE_MATSUM
  $       dt
       0.010
  $
  *DATABASE_NODFOR
  $       dt
       0.010
  $
  *DATABASE_NODAL_FORCE_GROUP
  $     nsid       cid
         201
  $
  *SET_NODE_LIST
  $      sid
         201
  $     nid1      nid2      nid3      nid4      nid5      nid6      nid7      nid8
         213       123
  $
  *DATABASE_NODOUT
  $       dt
       0.010
  $
  *DATABASE_HISTORY_NODE
  $      id1       id2       id3       id4       id5       id6       id7       id8
         123       233
  $
  *DATABASE_SECFORC
  $       dt
       0.010
  $
  *DATABASE_SWFORC
  $       dt
       0.010
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Constrain the Plates Together
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$  Three spotwelds across the plate, with failure defined.
  $
  *CONSTRAINED_SPOTWELD
  $       n1        n2        sn        sf         n         m
         212       122     7.854     4.534       2.0       2.0
         213       123     7.854     4.534       2.0       2.0
         214       124     7.854     4.534       2.0       2.0
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Boundary Motion Conditions
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$  Prescribe the velocity of the nodes on one end of the plate.
  $
  *BOUNDARY_PRESCRIBED_MOTION_SET
  $      nid       dof       vad      lcid        sf       vid
           1         1         0         1       1.0         0
  $
  *DEFINE_CURVE
  $     lcid      sidr      scla      sclo      offa      offo
           1
  $           abscissa            ordinate
                0.0000                 0.0
               10.0000              0.3048
               20.0000              0.3048
  $
  *SET_NODE_LIST
  $      sid
           1
  $     nid1      nid2      nid3      nid4      nid5      nid6      nid7      nid8
         231       232       233       234       235
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Contacts
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *CONTACT_AUTOMATIC_SINGLE_SURFACE
  $     ssid      msid     sstyp     mstyp    sboxid    mboxid       spr       mpr
           0
  $       fs        fd        dc        vc       vdc    penchk        bt        dt
  
  $      sfs       sfm       sst       mst      sfst      sfmt       fsf       vsf
  
  $ 
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Parts and Materials
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  *PART
  $      pid       sid       mid     eosid      hgid    adpopt
  plate_1 
           1         1         1
  plate_2
           2         1         1
  $
  $
  *MAT_PLASTIC_KINEMATIC
  $      mid        ro         e        pr      sigy      etan      beta
           1   2.70e-6      68.9     0.330     0.286   0.00689
  $      src       srp        fs
  
  $
  $$$$  Element formulation 6 (S/R Hughes-Liu) is used to prevent hourglassing.
  $
  *SECTION_SHELL
  $      sid    elform      shrf       nip     propt   qr/irid     icomp
           1         6                   3
  $       t1        t2        t3        t4      nloc
         2.0       2.0       2.0       2.0
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Cross Sections
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$  Two cross sections defined - one through each plate.  Two different
  $    methods for defining the cross sections are used.
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  $$$  cross section through plate 1
  $
  *DATABASE_CROSS_SECTION_PLANE
  $     psid       xct       yct       zct       xch       ych       zch
           0      30.0       0.0       0.0      31.0       0.0       0.0
  $     xhev      yhev      xhev      lenl      lenm
        30.0       1.0       0.0
  $
  $$$  cross section through plate 2
  $
  *DATABASE_CROSS_SECTION_SET
  $     nsid      hsid      bsid      ssid      tsid      dsid
           4                             2
  $
  *SET_NODE_LIST
  $      sid       da1       da2       da3       da4
           4
  $     nid1      nid2      nid3      nid4      nid5      nid6      nid7      nid8
         226       227       228       229       230
  $
  *SET_SHELL_LIST
  $      sid       da1       da2       da3       da4
           2 
  $     eid1      eid2      eid3      eid4      eid5      eid6      eid7      eid8
         221       222       223       224
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Nodes and Elements
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $
  *END

Figures

image01.gif

image02.gif

Animated Result

Result

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