Thermal thick and thin shells

Two metalstrips are heated up by a heat flux, which is applied at the bottom surface of the elements. One metalstrip is assigned to an element section which defines a thermal thick shell, the other is assigned to a thermal thin shell. A coupled structural-thermal analysis is performed to demonstrate the difference in the behaviour of the thermal thin and the thermal thick shell. The thermally thin shell has a constant temperature field over its thickness and expands only in length. The thermally thick shell, on the other hand, can map a temperature gradient across thickness, with the metal strip curving as a result of the change in thermal expansion across thickness.

*BOUNDARY_FLUX_SET
*BOUNDARY_SPC_SET
*CONTROL_HOURGLASS
*CONTROL_SHELL
*CONTROL_SOLUTION
*CONTROL_TERMINATION
*CONTROL_THERMAL_SOLVER
*CONTROL_THERMAL_TIMESTEP
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DATABASE_GLSTAT
*DATABASE_MATSUM
*DATABASE_SPCFORC
*DATABASE_TPRINT
*DEFINE_CURVE
*END
*INCLUDE
*KEYWORD
*MAT_ADD_THERMAL_EXPANSION
*MAT_ELASTIC
*MAT_THERMAL_ISOTROPIC
*PART
*SECTION_SHELL_THERMAL
*TITLE

*KEYWORD
$
$=============================CONTROL DEFINITIONS ==============================
$
*TITLE
Thermal thick and thin shells
*CONTROL_SOLUTION
$ coupled structural-thermal analysis
$     soln       nlq     isnan     lcint     lcacc     ncdcf
         2
*CONTROL_THERMAL_SOLVER
$ transient thermal analysis
$    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
                 0.5                       -1.0e-4
*CONTROL_THERMAL_TIMESTEP
$       ts       tip       its      tmin      tmax     dtemp      tscp      lcts
         1       1.0
*CONTROL_TERMINATION
$   endtim    endcyc     dtmin    endeng    endmas     nosol
       1.0
*CONTROL_HOURGLASS
$      ihq        qh
         8       0.1
$
*CONTROL_SHELL
$

$                                           thshel
                                                 1
$
$================================ OUTPUTDATA ===================================
$
*DATABASE_BINARY_D3PLOT
$       dt
       0.1
*DATABASE_GLSTAT
$       dt
       0.1
*DATABASE_MATSUM
$       dt
       0.1
*DATABASE_SPCFORC
$       dt
       0.1
*DATABASE_TPRINT
$       dt
       0.1
$
$============================== PART DEFINITIONS ===============================
$
*PART
$ title
metalstrip_shell_thick
$      pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         1         1         1         0         0         0         0         1
*PART
$ title
metalstrip_shell_thin
$      pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         2         2         1         0         0         0         0         1
$
$============================= SECTION PROPERTIES ==============================
$
*SECTION_SHELL_THERMAL
$    secid    elform      shrf       nip
         1        16
$       t1        t2        t3        t4
       3.0
$  ithelfm
         1
*SECTION_SHELL_THERMAL
$    secid    elform      shrf       nip
         2        16
$       t1        t2        t3        t4
       3.0
$  ithelfm
         2
$
$====================== MECHANICAL MATERIAL PROPERTIES =========================
$
*MAT_ELASTIC
$ steel
$      mid        ro         e        pr
         1   7.85e-9    210000      .285
*MAT_ADD_THERMAL_EXPANSION
$ steel
$      pid      lcid      mult     lcidy     multy     lcidz     multz
         1         0   12.0e-6
*MAT_ADD_THERMAL_EXPANSION
$ steel
$      pid      lcid      mult     lcidy     multy     lcidz     multz
         2         0   12.0e-6
$
$======================== THERMAL MATERIAL PROPERTIES ==========================
$
*MAT_THERMAL_ISOTROPIC
$ steel
$     tmid       tro     tgrlc    tgmult      tlat      hlat
         1   7.85e-9
$       hc        tc		 
    4.60e8      40.0
$
$=======================NODE/ELEMENT/SET/SEGMENT DEFINTIONS ====================
$
*INCLUDE
07_metalstrip_parts.k
$
$*SET_NODE_LIST_TITLE    structural_boundary    sid 1
$                      
$*SET_SEGMENT_TITLE       heat_flux_boundary    sid 1    
$
$====================== STRUCTURAL BOUNDARY CONDITIONS =========================
$
*BOUNDARY_SPC_SET
$ nid/nsid       cid      dofx      dofy      dofz     dofrx     dofry     dofrz
         1                   1         1         1         1         1         1
$
$==================== THERMAL BOUNDARY and INITIAL CONDITIONS ==================
$
*INITIAL_TEMPERATURE_SET
$     nsid      temp       loc
         0    293.15        -1
         0    293.15         0
         0    293.15         1
*BOUNDARY_FLUX_SET
$     ssid
         1
$     lcid      mlc1      mlc2      mlc3      mlc4       loc     nhisv
       101      -1.0      -1.0      -1.0      -1.0        -1
*DEFINE_CURVE
$     lcid      sidr       sfa       sfo      offa      offo    dattyp
       101         0         1         1         0         0         0
$   time    ,    heat flux
0.0,0.0
1.0,1000.0
2.0,1000.0
*END