*HEADING
: NAFEMS TEST NL4: SNAP-BACK UNDER DISPLACEMENT CONTROL
T2D2 ELEMENTS
*RESTART,WRITE
*NODE
1, -2500.,0.
9, 0.,25.
11, -10000.,0.
*NGEN
1,9
*ELEMENT,TYPE=T2D2,ELSET=K2
1, 1,9
*ELEMENT,TYPE=SPRING1,ELSET=K3
11, 1
*ELEMENT,TYPE=SPRING1,ELSET=K1
12, 9
*ELEMENT,TYPE=SPRING2,ELSET=K4
13, 1,11
*SOLID SECTION,ELSET=K2,MATERIAL=M1
1.0, 
*MATERIAL,NAME=M1
*ELASTIC
5.0E7, 
*SPRING,ELSET=K1
2,
1.5,
*SPRING,ELSET=K3
1,
0.25,
*SPRING,ELSET=K4
1,1
1.0,
*BOUNDARY
1,2
9,1
11,2
** 
*STEP,NLGEOM,INC=200
*STATIC,RIKS
0.01,1.,,0.04,1.
*CLOAD
11,1,4000.
*CONTROLS, PARAMETERS=FIELD

,0.0,
*NODE PRINT
CF,U
*NODE FILE
CF,U
*EL PRINT,F=0
*ENDSTEP