Structure-thermal coupled analysis I — Welcome to LS-DYNA Examples

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In this example a steel frame is subjected to a thermal load which results in thermal expansion of the structure. The simulation is set up as a structure-thermal coupled analysis using (static) imph2cit time integration. For the definition of the thermal load the keyword *BOUNDARY_TEMPERATURE is used and temperature fields are calculated by the thermal solver. The temperature fields are handend over to the structural solver which calculates thermal expansion due to the temperature field. The temperature of the steel frame is initially at 20.0 °C and is ramped up to 200 °C. Thermal material properties are defined with *MAT_THERMAL_ISOTROPIC for the thermal solver. The temperature dependent material properties for the strucural solver, h2ke thermal expansion coefficient, are defined with *MAT_ELASTIC_PLASTIC_THERMAL.

Keywords

*BOUNDARY_SPC_SET
*BOUNDARY_TEMPERATURE_SET
*CONTROL_ACCURACY
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_SOLUTION
*CONTROL_SOLUTION
*CONTROL_TERMINATION
*CONTROL_THERMAL_SOLVER
*CONTROL_THERMAL_TIMESTEP
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DATABASE_GLSTAT
*DATABASE_MATSUM
*DEFINE_CURVE
*END
*INCLUDE
*INITIAL_TEMPERATURE_SET
*KEYWORD
*MAT_ELASTIC_PLASTIC_THERMAL
*MAT_THERMAL_ISOTROPIC
*PART
*SECTION_SHELL
*SET_NODE_GENERAL
*SET_NODE_LIST_TITLE
*TITLE

Reduced Input

*KEYWORD
$
$=============================CONTROL DEFINITIONS ==============================
$
*TITLE
Steel frame - structure-thermal coupled analysis
*CONTROL_SOLUTION
$     soln       nlq     isnan     lcint     lcacc     ncdcf
         2
*CONTROL_THERMAL_SOLVER
$    atype     ptype    solver     cgtol       gpt    eqheat     fwork       sbc
         1         1        11
$   msglvl    maxitr    abstol    reltol     omega                           tsf

*CONTROL_TIMESTEP
$   dtinit    tssfac      isdo    tslimt     dt2ms      lctm     erode     ms1st
                 0.9
*CONTROL_THERMAL_TIMESTEP
$       ts       tip       its      tmin      tmax     dtemp      tscp      lcts
         1
*CONTROL_TERMINATION
$   endtim    endcyc     dtmin    endeng    endmas     nosol
       1.0
*CONTROL_ACCURACY
$      osu       inn    pidosu      iacc
         1         4                   1
$--------1---------2---------3---------4---------5---------6---------7---------8
$ IMPLICIT CONTROL CARDS
$--------1---------2---------3---------4---------5---------6---------7---------8
*CONTROL_IMPLICIT_GENERAL
$   imflag       dt0    imform      nsbs       igs     cnstn      form    zero_v
         1       0.1                            
*CONTROL_IMPLICIT_SOLUTION
$   nsolvr    ilimit    maxref     dctol     ectol     rctol     lstol    abstol
        12                        0.0010   0.01000                       1.0E-20
$    dnorm    diverg     istif   nlprint    nlnorm
         0         0         0         1         4
$
$================================ OUTPUTDATA ===================================
$
*DATABASE_BINARY_D3PLOT
$       dt
       0.1
*DATABASE_GLSTAT
$       dt
       0.1
*DATABASE_MATSUM
$       dt
       0.1
$
$============================== PART DEFINITIONS ===============================
$
*PART
$ title
column_1
$      pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         1         1         1                                                 1
*PART
$ title
bar
$      pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         2         1         1                                                 1
*PART
$ title
column_2
$      pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         3         1         1                                                 1
$
$============================= SECTION PROPERTIES ==============================
$
*SECTION_SHELL
$      sid    elform      shrf       nip     propt   qr/irid     icomp
         1       -16     0.833       5.0
$       t1        t2        t3        t4
       3.0       3.0       3.0       3.0
$
$====================== MECHANICAL MATERIAL PROPERTIES =========================
$
*MAT_ELASTIC_PLASTIC_THERMAL
$      mid        ro
         1   7.85e-9
$       t1        t2
         0       400
$       e1        e2
    210000    210000
$      pr1       pr2
       0.3       0.3
$   alpha1    alpha2
     12e-6     12e-6
$    sigy1     sigy2
       500       500
$    etan1     etan2
     10000     10000
$
$======================== THERMAL MATERIAL PROPERTIES ==========================
$
*MAT_THERMAL_ISOTROPIC
$     tmid       tro     tgrlc    tgmult      tlat      hlat
         1   7.85e-9
$       hc        tc        
    4.60e8      40.0
$
$================= THERMAL BOUNDARY AND INITIAL CONDITIONS =====================
$
*INITIAL_TEMPERATURE_SET
$  nid/sid     tlcid       loc
         0        20
$
*BOUNDARY_TEMPERATURE_SET
$  nid/sid     tlcid     tmult       loc    tdeath    tbirth
         1       101       1.0
$
*DEFINE_CURVE
$     lcid
       101
$ time,temp
0,20
1,200
$
$====================== MECHANICAL BOUNDARY CONDITIONS =========================
$
*BOUNDARY_SPC_SET
$ nid/nsid       cid      dofx      dofy      dofz     dofrx     dofry     dofrz
         2                   1         1         1         1         1         1
*BOUNDARY_SPC_SET
$ nid/nsid       cid      dofx      dofy      dofz     dofrx     dofry     dofrz
         3                   1         1         1         1         1         1
$=======================NODE/ELEMENT/SET/SEGMENT DEFINTIONS ====================
*INCLUDE
geo.k
$
*SET_NODE_GENERAL
$      sid
         1
$   option
       ALL
*SET_NODE_LIST_TITLE
fixing_1
$      sid       da1       da2       da3       da4    solver
         2 
$     nid1      nid2      nid3      nid4      nid5      nid6      nid7      nid8
         4         1         3         2                                        
*SET_NODE_LIST_TITLE
fixing_2
$      sid       da1       da2       da3       da4    solver
         3 
$     nid1      nid2      nid3      nid4      nid5      nid6      nid7      nid8
       161       163       164       162
$
$--------1---------2---------3---------4---------5---------6---------7---------8
$
*END

Figures

exp_mat_thermal_result1.png

exp_mat_thermal_result2.png

Animated Result

mat_thermal.gif

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