*HEADING
: SIMPLE CONTACT TEST, POSITIVE GAP CLEARANCE  [GAPSPHER]
Linear Perturbation steps with *LOAD CASE
*NODE
11,0.0
*NODE,NSET=GAP
21,5.0
121,5.0
*ELEMENT,TYPE=B31,ELSET=BEAM
1,11,21
*BEAM SECTION,SECTION=CIRC,ELSET=BEAM,MATERIAL=STEEL
0.25, 
*MATERIAL,NAME=STEEL
*ELASTIC
30.E6,.3
*ELEMENT,TYPE=GAPSPHER,ELSET=RAD
121,21,121
*GAP,ELSET=RAD
.0208, 
*STEP,NLGEOM,INC=20
*STATIC
.25,1.
*BOUNDARY
11,1,6
121,1,6
*CLOAD
21,2,2.E4
21,3,3.E4
*EL PRINT
S,E
*NODE PRINT
COORD,U
*OUTPUT,FIELD,FREQ=999
*ELEMENT OUTPUT,ELSET=RAD
S,E
*OUTPUT,FIELD,FREQ=999
*NODE OUTPUT,NSET=GAP
U,
RF,
*END STEP



*STEP,PERTURBATION
*STATIC
*LOAD CASE,NAME="CLOAD-1"
*CLOAD
21,2,2.E4
21,3,3.E4
*END LOAD CASE
*LOAD CASE,NAME="CLOAD-2"
*CLOAD
21,2,4.E4
21,3,6.E4
*END LOAD CASE
*OUTPUT,FIELD,FREQ=999
*NODE OUTPUT,NSET=GAP
U,
RF,
*END STEP