Damping

A simple model of a tire is placed under gravity loading and drops onto rigid solid elements. Fully integrated shell elements are used for the tire to prevent hourglassing from damping out the model. Additionally, rigid solid elements are used for modeling the ground instead of a rigidwall because the rigidwall will also damp the system because of its' perfectly plastic contact definition. Thus, to damp out the bouncing, global damping is applied to the system.

*DAMPING_GLOBAL
Tire Bounces on the Ground and Damps Out
LS-DYNA Manual Section: *DAMPING_GLOBAL

Additional Sections:
*CONTROL_DAMPING
*LOAD_BODY_Z

Example: Tire Bounces on the Ground and Damps Out

Filename: damping.tire.k

Description:
A simple model of a tire is placed under gravity loading and drops onto rigid
solid elements. Fully integrated shell elements are used for the tire to
prevent hourglassing from damping out the model. Additionally, rigid solid
elements are used for modeling the ground instead of a rigidwall because the
rigidwall will also damp the system because of its' perfectly plastic contact
definition. Thus, to damp out the bouncing, global damping is applied to the
system.

Model:
Global damping of 0.5 is applied to the system using the *D AMPING_GLOBAL
keyword. Contact between the tire and ground is defined using node to surface
contact. Gravity is applied with the *LOAD_BODY_Z command.

Results:
The total energy of the system comes from the external energy of gravity
(potential energy of "mgh"). This energy is absorbed by the damping in the
model.

*CONTACT_NODES_TO_SURFACE
*CONTROL_DYNAMIC_RELAXATION
*CONTROL_ENERGY
*CONTROL_OUTPUT
*CONTROL_TERMINATION
*DAMPING_GLOBAL
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_GLSTAT
*DATABASE_HISTORY_NODE
*DATABASE_MATSUM
*DATABASE_NODOUT
*DATABASE_RCFORC
*DATABASE_RWFORC
*DEFINE_CURVE
*ELEMENT_MASS
*ELEMENT_SHELL
*ELEMENT_SOLID
*END
*KEYWORD
*LOAD_BODY_Z
*MAT_PIECEWISE_LINEAR_PLASTICITY
*MAT_RIGID
*NODE
*PART
*SECTION_SHELL
*SECTION_SOLID
*TITLE

  *KEYWORD
  *TITLE
  A simple tire bouncing on the ground with damping.
  $
  $  LSTC Example
  $
  $  Last Modified: October 13, 1997
  $
  $
  $  Units: mm, kg, ms, kN, GPa, kN-mm
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Control Ouput
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *CONTROL_TERMINATION 
  $   endtim    endcyc     dtmin    endeng    endmas
       40.01
  $
  *CONTROL_ENERGY
  $     hgen      rwen    slnten     rylen
           2         2         2         2
  $
  *CONTROL_OUTPUT
  $    npopt    neecho    nrefup    iaccop     opifs    ipnint    ikedit
           1         3
  $
  $
  *DATABASE_BINARY_D3PLOT
  $       dt       lcdt 
        10.0
  $
  *DATABASE_BINARY_D3THDT
  $       dt       lcdt 
      999999
  $
  *DATABASE_GLSTAT
  $       dt
         0.1
  $
  *DATABASE_MATSUM
  $       dt
         0.1
  $      
  *DATABASE_NODOUT
  $       dt
         0.1
  $
  *DATABASE_HISTORY_NODE
  $      id1       id2       id3       id4       id5       id6       id7       id8
        8914      8746      8918
  $
  *DATABASE_RCFORC
  $       dt
         0.1
  $
  *DATABASE_RWFORC
  $       dt
         0.1
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Damping
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *DAMPING_GLOBAL
  $     lcid    valdmp
           0       0.5
  $
  $
  *CONTROL_DYNAMIC_RELAXATION
  $   nrcyck     drtol    drfctr    drterm    tssfdr    irelal     edttl    idrflg
         100    1.0e-3     0.995                 0.9
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Gravity
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *LOAD_BODY_Z
  $     lcid        df    lciddr        xc        yc        zc
           1 9.810E-03
  $
  $
  *DEFINE_CURVE
  $     lcid      sidr      scla      sclo      offa      offo
           1
  $
  $           abscissa            ordinate
                  0.00               1.000
               1000.00               1.000
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Contacts - sliding interface definitions
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  $$$$  Prevent the nodes of the tire from penetrating the ground.
  $
  *CONTACT_NODES_TO_SURFACE
  $
  $     ssid      msid     sstyp     mstyp    sboxid    mboxid       spr       mpr
          36        76         3         3
  $
  $       fs        fd        dc        vc       vdc    penchk        bt        dt
  
  $
  $      sfs       sfm       sst       mst      sfst      sfmt       fsf       vsf
  
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Parts and Materials
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *PART
  $      pid       sid       mid     eosid      hgid      grav    adpopt
  wheel
          35         1         1
  tire
          36         1         1
  ground
          76        76         2
  $
  $
  $$$$  Materials
  $
  *MAT_PIECEWISE_LINEAR_PLASTICITY
  $      mid        ro         e        pr      sigy      etan      eppf      tdel
           1 0.783E-05     200.0       0.3     0.207               0.750
  $  Cowper/Symonds Strain Rate Parameters
  $        C         p      lcss      lcsr
          40         5
  $  Plastic stress/strain curves
       0.000     0.080     0.160     0.400     1.000
       0.207     0.250     0.275     0.290     0.300
  $
  $ 
  *MAT_RIGID
  $      mid        ro         e        pr         n    couple         m     alias
           2 0.783E-05     200.0       0.3  
  $
  $      cmo      con1      con2
         1.0         7         7
  $
  $   lco/a1        a2        a3        v1        v2        v3
  
  $
  $
  $$$$  Sections
  $
  *SECTION_SHELL
  $      sid    elform      shrf       nip     propt   qr/irid     icomp
           1         6              3.0000
  $       t1        t2        t3        t4      nloc
        1.00      1.00      1.00      1.00
  $ 
  $ 
  *SECTION_SOLID
          76         1
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Nodes and Elements
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  $
  *END