/INTER/TYPE6

Block Format Keyword

/INTER/TYPE6 - Contact between two rigid bodies with tabulated input of the contact force

Description

This interface is used to simulate contact between two rigid bodies with tabulated input of the contact force. It works similar to interface TYPE3. Contact force between the bodies can be input as a function of maximal penetration. The interface also allows you to input a force function for unloading.

The following conditions should be fulfilled for this interface:

•	the segments of two contact surface must face each other (example: the surface normals must be oriented from one surface to the other)

•	the interface only works with segments connected to solid or shell elements; two contact surface must not share the same node (must be part of 2 different rigid bodies)

•	user-defined interface stiffness can reduce the time step

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/INTER/TYPE6/inter_ID/unit_ID
inter_title
surf_ID1	surf_ID2
Sfric		Fric		Gap		Tstart		Tstop
	IRS	IRM	Inacti	fct_IDff	fct_IDfv	Ascalef		Ascalev
fct_IDId	Iform	Ascalex		FscaleId		Icor
fct_IDul		Stiff		Fscaleul
Visc		fct_IDdv	fct_IDdf	Fscalev

Field	Contents	SI Unit Example
inter_ID	Interface identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
inter_title	Interface title (Character, maximum 100 characters)
surf_ID1	Rigid surface 1 identifier (Integer)
surf_ID2	Rigid surface 2 identifier (Integer)
Sfric	Static friction force (Real)
Fric	Coulomb friction (Real)
Gap	Gap for impact activation (Real)
Tstart	Interface activation time Default = 0.0 (Real)
Tstop	Interface deactivation time Default = 1.0e30 (Real)
IRS	Renumbering flag for segments of the first surface (Integer) = 0: if segment is connected to a solid element, its normal is reversed if entering the solid element (the segment is renumbered) = 1: normal is always reversed (segment 1234 is read 2143) = 2: normal is never reversed (segments connected to a solid element are not renumbered)
IRM	Renumbering flag for segments of the second surface (same as IRS) (Integer) = 0: if segment is connected to a solid element, its normal is reversed if entering the solid element (the segment is renumbered) = 1: normal is always reversed (segment 1234 is read 2143) = 2: normal is never reversed (segments connected to a solid element are not renumbered)
Inacti	Deactivation flag of stiffness in case of initial penetrations (Integer) =0: no action =5: gap is variable with time and initial gap is adjusted as follows: where, P0 is the initial penetration (see figure in Comment 7 of /INTER/TYPE7)
fct_IDff	Friction multiplier function vs. normal force (Integer)
fct_IDfv	Friction multiplier function vs. sliding velocity (Integer)
Ascalef	Abscissa scale factor for velocity functions (fct_IDff and fct_IDdv) (Real)
Ascalev	Abscissa scale factor for force functions (fct_IDff and fct_IDdv) (Real)
fct_IDId	Force vs penetration curve function identifier (Integer)
Iform	Formulation flag (Comment 1) (Integer) = 0: elastic contact = 1: nonlinear contact
Ascalex	Abscissa scale factor on fct_IDId and fct_IDul Default = 1.0 (Real)
FscaleId	Ordinate scale factor on fct_IDId Default = 1.0 (Real)
Icor	Adjusting force flag, due to initial intersection (Comment 2) (Integer) =0: off =1: on
fct_IDul	Force vs penetration curve for unload function identifier (Integer)
Stiff	Loading/unloading stiffness Default =1.0e30 (Real)
Fscaleul	Ordinate scale factor for unload fct_IDul Default = 1.0 (Real)
Visc	Damping coefficient (Real)
fct_IDdv	Damping force function vs. penetration velocity (Integer)
fct_IDdf	Damping multiplier function vs. normal force (Integer)
Fscalev	Ordinate scale factor on fct_IDdv (Real)

1.	The loading curve fct_IDId should always be given.

For Iform =0, the unloading curve is not considered and loading and unloading use the same curve fct_IDId.

For Iform =1, the unloading curve fct_IDul is considered and:

•	when the unloading curve fct_IDul is not defined, then loading follows the fct_IDId and unloading follows a straight curve with slope Stiff down to zero and remain equal to zero. Reloading RADIOSS jumps from zero to the loading function fct_IDId along a straight curve with slope Stiff.

•

when both the loading and unloading curves are defined (the unloading curve should be lower than the loading curve) then during unloading RADIOSS jumps from loading to unloading curve following a straight curve with slope Stiff. Reloading RADIOSS jumps from fct_IDul unloading curve to loading curve fct_IDId along a straight curve with slope Stiff.

Some of the cases are shown below:

starter_inter_type6

Iform = 0

starter_inter_type6A

Iform = 1

2.	If Iform =1 and Icor =1, the interface force at t=0 is set to a value from the unloading function fct_IDul, which corresponds to the initial penetration. If the unloading function is not defined, the initial force is set to zero.

3.	Tangent friction force, Ft is calculated as follows:

Where, Fn is the normal force, and is dynamic friction coefficient defined as:

Where, vt is the sliding velocity, fff and ffv are functions of fct_IDff and fct_IDfv

4.	Damping force, Fdamp is calculated as follows:

With, vn being the penetration velocity, fdf and fdv are functions of fct_IDdf and fct_IDdv

/INTER/TYPE6

/INTER/TYPE6

/INTER/TYPE6

Format

See Also: