*heading
 Test of a small spotweld inside a 4-node shell element
     
          -->|   |<-- delx
    21 o-----o---+---------o
       |     |22           |23
    |  |     |             |
    -  o-----o-------------o
       |11   |12           |13 
    -  +     |   X         |   
    ^  |     |             |       
    |  |     |             |       X - spotweld at (0,0,0), always inside
  dely |     |             |           element 2
       |     |             |
       o-----o---+---------o
       1     2             3
*preprint, echo=yes, model=yes
*parameter
 step_time=1.e-3
 time_interval = step_time*0.01
 square_side = 20.0
 corner      = square_side/2.0
 xsw         = 0.0
 ysw         = 0.0
** Skew the middle node in the x- and y-direction
 delx = 3.333333333333
 dely = 3.333333333333
 x1  = -corner
 y1  = -corner
 x3  =  corner
 y3  = -corner
 x23 =  corner
 y23 =  corner
 x21 = -corner
 y21 =  corner
 x2  = -delx
 y2  = -corner
 x11 = -corner
 y11 =  dely
 x12 = -delx
 y12 =  dely
 x13 =  corner
 y13 =  dely
 x22 = -delx
 y22 =  corner
 z = -3.0
*node,nset=nall-top
  1,  <x1>,  <y1>, 0.0
  2,  <x2>,  <y2>, 0.0
  3,  <x3>,  <y3>, 0.0
 11, <x11>, <y11>, 0.0
 12, <x12>, <y12>, 0.0
 13, <x13>, <y13>, 0.0
 21, <x21>, <y21>, 0.0
 22, <x22>, <y22>, 0.0
 23, <x23>, <y23>, 0.0
 1001, <xsw>, <ysw>, 0.0
*node,nset=nall-bot
 101,  <x1>,  <y1>, <z>
 102,  <x2>,  <y2>, <z>
 103,  <x3>,  <y3>, <z>
 111, <x11>, <y11>, <z>
 112, <x12>, <y12>, <z>
 113, <x13>, <y13>, <z>
 121, <x21>, <y21>, <z>
 122, <x22>, <y22>, <z>
 123, <x23>, <y23>, <z>
*element, type=s4, elset=shell
 1, 1, 2, 12, 11
 2, 2, 3, 13, 12
 3, 11, 12, 22, 21
 4, 12, 13, 23, 22
*shell general section, elset=shell, material=mat
 3.0,
*element, type=s4, elset=base
 101, 101, 102, 112, 111
 102, 102, 103, 113, 112
 103, 111, 112, 122, 121
 104, 112, 113, 123, 122
*shell general section, elset=base, material=mat
 3.0,
*material, name=mat
*elastic
 1.e6, 0.0
*contact pair, interaction=smooth, type=surface to surface
 top, bot
*surfaceinteraction, name=smooth
*************************************************
*nset, nset=n1001
 1001,
*surface, name=top, type=element
 shell, sneg
*surface, name=bot, type=element
 base, spos
*fastener, interaction name=spot, reference node set=n1001,property=spotprop,coupling=structural
 top, bot
*fastener property, name=spotprop
 0.01,
 1,6
*boundary
 nall-bot, 1,6
*************************************************
*step,nlgeom=yes
*static
 0.05, 1.
*cload
  1, 3, 2.5e5
  3, 3, 2.5e5
 21, 3, 2.5e5
 23, 3, 2.5e5
*output,field, freq=2
*node output
 u,
*contact output
 cstress,
*nset,nset=QA_TEST
 1,3,21,23
*OUTPUT, HISTORY
*node output,nset=QA_TEST
 u,
*end step