Contact — Gap Spring

ContactPASS · 0%

Unilateral, frictional, sliding, or interference-contact verification. Checks: gap activation complementarity and reaction sign.

Tolerance:: 5%

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Problem statement

Geometry: One DOF node attached to k=1000 N/mm spring with rigid stop at g=1 mm; apply force F from 0 to 1500 N.
Material: Constitutive or analytical definition: Signorini conditions g>=0, Rc>=0, g Rc=0 combined with the linear spring equilibrium.
Boundary conditions: Required solver capability: frictionless_unilateral_contact. Use the loading/path control stated in the setup and preserve the complete response history.
Measured quantity: For F<=1000 N: u=F/k and Rc=0. For F>1000 N: u=1 mm and Rc=F-1000 N. Never allow tensile contact force.

WebCAE Terminal

Paste these commands into the Terminal panel inside WebCAE. They use the same text DSL as the application; run one command per line:

units mm
material E=1e9 nu=0.0
box width=1.0 depth=1.0 height=1.0
box width=0.6 depth=0.6 height=1.0
contact frictionless slave="surface number 11" master="surface number 6"
mesh tet size=0.5 order=1 bonding=0
fix surface number 1
fix surface number 7 component=x
fix surface number 8 component=y
spring surface number 11 stiffness=1000 component=z
load surface number 12 force=-1500 component=z
solve nonlinear steps=6
extract reaction target="surface number 6"

Results comparison

Reference value	500.0000 N (Rc=F-1000 N, u=1.0000 mm at F=1500 NRc=0, u=0.5000 mm at F=500 N)
Our result	499.9988 N (u=1.00000 mm at F=1500 NRc=0.0000 N, u=0.50000 mm at F=500 N)
Deviation	0%
Tolerance	5%
Status	PASS · 0%
Element family	Solid element
Mesh details	16 nodes, 12 tet4 elements + elastic spring k=1000 N/mm, initial gap g0=1.0 mm, eps_N=4e8 N/mm

Updated: 2026-10-27 · version not recorded