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!CONTACT¶

Definition of contact conditions

Parameters¶

GRPID       = boundary condition group ID
INTERACTION = SSLID(small-sliding contact, default) / FSLID(finite-sliding contact) / TIED(tied constraint)
NTOL        = contact-normal convergence threshold (default: 1.e-5)
TTOL        = contact-tangential convergence threshold (default: 1.e-3)
NPENALTY    = contact-normal penalty (default: stiffness matrix × 1.e3)
TPENALTY    = contact-tangential penalty (default: 1.e3)
DAMP_ALPHA  = contact damping coefficient (dimensionless; default: 0.0 = no damping)
DAMP_GACT   = contact damping activation distance (unit of length; default: 0.0 = no damping)
CONTACTPARAM = contact detection parameter set name (specified by !CONTACT_PARAM, NAME)

** Second and subsequent lines **

When `INTERACTION = SSLID, FSLID`¶

(2nd line) PAIR_NAME, fcoef, factor

Variable	Type	Description
PAIR_NAME	C	Contact pair name (defined by `!CONTACT PAIR`)
fcoef	R	Friction coefficient (default: 0.0)
factor	R	Friction penalty stiffness

When `INTERACTION = TIED`¶

(2nd line) PAIR_NAME

Variable	Type	Description
PAIR_NAME	C	Contact pair name (defined by `!CONTACT PAIR`)

Example¶

!CONTACT_ALGO, TYPE=SLAGRANGE
!CONTACT, GRPID=1, INTERACTION=FSLID
  CP1, 0.1, 1.0e+5

When using contact damping

!CONTACT_ALGO, TYPE=SLAGRANGE
!CONTACT, GRPID=1, INTERACTION=FSLID, DAMP_ALPHA=1.0e-2, DAMP_GACT=2.0e-2
  CP1, 0.0, 5.0e+2

Notes¶

When CONTACTPARAM is specified, the referenced !CONTACT_PARAM must be defined before the !CONTACT card. If this parameter is omitted, the default contact detection parameter set is used.
Contact damping is enabled only when both DAMP_ALPHA and DAMP_GACT are positive. It does not operate if only one of them is specified.
For an overview of contact damping and guidance on choosing the damping coefficient and activation distance, see Function Reference: Contact and Embedding.