PCNTX11

Bulk Data Entry

PCNTX11 – Extended Contact (CONTX11) Property type 11 for Geometric Nonlinear Analysis

Description

Defines properties type 11 of a CONTACT interface for geometric nonlinear analysis.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
PCNTX11	PID		ISTF		IGAP			IDEL
	STMIN	STMAX	MESHSIZE	DTMIN
	STFAC	FRIC	GAP	TSTART	TEND	STF1
	IBC			INACTI	VISS	VISF	BMULT

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
PCONT	34
PCNTX11	34

Field	Contents
PID	Property identification number of the associated PCONT. No default (Integer > 0)
ISTF	Stiffness definition flag (See comment 5). Default as defined by CONTPRM (Integer = 0, …, 5) 0 - STFAC is a stiffness scale factor and the stiffness is computed according to the master side characteristics. 1 - STIF1 is used as interface stiffness. 2, 3, 4 and 5 - STFAC is a stiffness scale factor and the interface stiffness is computed from both master and slave characteristics.
IGAP	Gap definition flag. Default as defined by CONTPRM (Character = CONST, VAR, or VAR3) CONST - Gap is a constant and equal to GAP. VAR - Gap is a variable (in space, not in time) according to the characteristics of the impacted master line and the impacting slave nodes (See comment 6). VAR3 - Gap is a variable according to the characteristics of the impacted master line and impacting slave node + gap is taken into account the size of the elements.
IDEL	Flag for node and segment deletion. Default as defined by CONTPRM (Integer = 0, 1, or 2) 0 - No deletion. 1 - When all the elements (shells and solids) associated to one segment are deleted, the segment is removed from the master side of the interface. Additionally, non-connected nodes are removed from the slave side of the interface. 2 - When a shell or a solid element is deleted, the corresponding segment is removed from the master side of the interface. Additionally, non-connected nodes are removed from the slave side of the interface.
STMIN	Minimum stiffness (Only with ISTF > 1). Default as defined by CONTPRM (Real > 0)
STMAX	Maximum stiffness (Only with ISTF > 1). Default as defined by CONTPRM (Real > 0)
MESHSIZE	Percentage of mesh size (Used only when IGAP = VAR3). Default = 0.4 (Real, 0.0 < MESHSIZE < 1.0)
DTMIN	Limiting nodal time step (see comment 10) No default (Real > 0)
STFAC	Interface stiffness scale factor (Only with ISTF ≠ 1). Default as defined by CONTPRM (Real > 0)
FRIC	Coulomb friction. Default as defined by CONTPRM (Real > 0)
GAP	Gap for impact activation (See comment 6). Default as defined by CONTPRM (Real > 0)
TSTART	Start time. Default = 0.0 (Real > 0)
TEND	Time for temporary deactivation. Default = 1030 (Real > 0)
STIF1	Interface stiffness (Only with ISTF = 1). Default = 0.0 (Real > 0)
IBC	Flag for deactivation of boundary conditions at impact applied to the slave grid set. Default as defined by CONTPRM (Character = X, Y, Z, XY, XZ, YZ, or XYZ)
INACTI	Handling of initial penetrations flag (See comment 7). Default as defined by CONTPRM (Integer = 0, 1, 2, 3, 5, or 6) 0 - No action. 1 - Deactivation of stiffness on nodes. 2 - Deactivation of stiffness on elements. 3 - Change slave node coordinates to avoid small initial penetrations. 5 - GAP is a variable with time and initial gap is adjusted as follows: gap0 = gap - P0 6 - Gap is variable with time but initial gap is slightly de-penetrated as follows: gap0 = gap - P0 – 0.05*(gap - P0) Invalid entries are ignored.
VISS	Critical damping coefficient on interface stiffness. Default as defined by CONTPRM (Real > 0)
VISF	Critical damping coefficient on interface friction. Default as defined by CONTPRM (Real > 0)
BMULT	Sorting factor. Can be used to speed up the sorting algorithm and is machine-dependent. Default as defined by CONTPRM (Real > 0)

Comments

1.	The property identification number must be that of an existing PCONT bulk data entry. Only one PCNTX11 property extension can be associated with a particular PCONT.

2.	PCNTX11 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS = EXPDYN. It is ignored for all other subcases.

3.	If FRIC is not explicitly defined on the PCONTX/PCNTX# entries, the MU1 value on the CONTACT or PCONT entry is used for FRIC in the /INTER entries for Geometric Nonlinear Analysis. Otherwise, FRIC on PCONTX/PCNTX# overwrites the MU1 value on CONTACT/PCONT.

4.	PCNTX11 defines the properties of contact interface type CONTX11, it describes the edge to edge or line to line interface. This interface simulates impact between lines, a line can be a beam or truss element or a shell edge or spring elements. The interface properties are:

•	impacts occur between a master and a slave line

•	a slave line can impact on one or more master lines

•	a line can belong to the master and the slave side. This allows self impact.

•	this interface can be used in addition to the interface type 7 PCNTX7 to solve the edge to edge limitation of interface type 7

5.	If ISTF ≠ 1, the interface stiffness K is computed from the master segment stiffness Km and/or the slave segment stiffness Ks.

The master stiffness is computed from Km = STFAC * B * S * S/V for solids, Km = 0.5 * STFAC * E * t for shells.

The slave stiffness is an equivalent nodal stiffness computed as Ks = STFAC * B * V-3 for solids, Ks = 0.5 * STFAC * E * t for shells.

In these equations, B is the Bulk Modulus, S is the segment area, and V is the volume of a solid. There is no limitation to the value of stiffness factor (but a value larger than 1.0 can reduce the initial time step).

The interface stiffness is K = max (STMIN, min (STMAX, K1)) with:

•	ISTF = 0, K1 = Km

•	ISTF = 2, K1 = 0.5 * (Km + Ks)

•	ISTF = 3, K1 = max (Km, Ks)

•	ISTF = 4, K1 = min (Km, Ks)

•	ISTF = 5, K1 = Km * Ks / (Km + Ks)

6.	If IGAP = VAR, the variable gap is computed as: gm + gs

with:

•	gm - master element gap with

gm = t/2, t: thickness of the master element for shell elements.

gm = L/10, L - length of the smallest side of a solid element.

gm = 1/2√ for truss and beam elements, with S being the cross section of the element.

gm = 0 for spring elements.

•	gs - slave element gap is computed as the same way.

If the slave node is connected to multiple shells and/or beams or trusses, the largest computed slave gap is used.

The variable gap is always at least equal to GAP.

7.	INACTI = 3, is only recommended for small initial penetrations and should be used with caution because:

•	the coordinate change is irreversible

•	it may create other initial penetrations, if several surface layers are defined in the interfaces

•	it may create initial energy, if the node belongs to a spring element

INACTI = 5 is recommended for airbag simulation deployment.

INACTI = 6 is recommended instead of INACTI = 5, in order to avoid high frequency effects into the interfaces.

Inacti_flag_6

8.	Slave segment is deactivated from the contact when the segment kinematic time step calculated for this contact becomes smaller than DTMIN.