/INTER/TYPE6

Block Format Keyword 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 maximum penetration. The interface also allows you to input a force function for unloading.

Description

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 surfaces 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

Definition

Field Contents SI Unit Example
inter_ID Interface identifier.

(Integer, maximum 10 digits)

unit_ID 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)

[ N ]
Fric Coulomb friction.

(Real)

Gap Gap for impact activation.

(Real)

[ m ]
Tstart Interface activation time.

Default = 0.0 (Real)

[ s ]
Tstop Interface deactivation time.

Default = 1.0e30 (Real)

[ s ]
IRS Renumbering flag for segments of the first surface.
= 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).

(Integer)

IRm Renumbering flag for segments of the second surface (same as IRS).
= 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).

(Integer)

Inacti Deactivation flag of stiffness in case of initial penetrations.
= 0
No action.
= 5
Gap is variable with time and initial gap is adjusted as:
gap 0 = Gap P 0
Where, P 0 is the initial penetration. 7

(Integer)

fct_IDff Friction multiplier function versus normal force.

(Integer)

fct_IDfv Friction multiplier function versus sliding velocity.

(Integer)

Ascalef Abscissa scale factor for velocity functions (fct_IDff and fct_IDdv).

(Real)

[ m s ] MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaada Wcaaqaaiaab2gaaeaacaqGZbaaaaGaay5waiaaw2faaaaa@39DE@
Ascalev Abscissa scale factor for force functions (fct_IDff and fct_IDdv).

(Real)

[ N ]
fct_IDId Force versus penetration curve function identifier.

This function should be positive in both force and displacement.

(Integer)

Iform Contact formulation flag. 1
= 0
Nonlinear elastic.
= 1
Nonlinear elasto-plastic with an unloading curve which must be defined.
= 2
Nonlinear elasto-plastic with decoupled hardening.

(Integer)

Ascalex Abscissa scale factor on fct_IDId and fct_IDul.

Default = 1.0 (Real)

[ m ]
FscaleId Ordinate scale factor on fct_IDId.

Default = 1.0 (Real)

[ N ]
Icor Adjusting force flag, due to initial intersection. 2
= 0
Off
= 1
On

(Integer)

fct_IDul Force versus penetration curve for unload function identifier.

This function should be positive in both force and displacement and always less than the loading curve.

Not used if Iform = 2.

(Integer)

Stiff Loading/unloading stiffness used when transitioning between curves.

Required input if Iform = 1, 2.

[ N m ]
Fscaleul Ordinate scale factor for unload fct_IDul.

Default = 1.0 (Real)

[ N ]
Visc Damping coefficient.

(Real)

[ Ns m ]
fct_IDdv Damping force function versus penetration velocity.

(Integer)

fct_IDdf Damping multiplier function versus normal force.

(Integer)

Fscalev Ordinate scale factor on fct_IDdv.

(Real)

[ N ]

Comments

  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:
    Figure 1. Iform = 0

    starter_inter_type6
    Figure 2. Iform = 1

    starter_inter_type6a
    Figure 3. Iform = 2


  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:
    F t = Sfric + μ ( F n , F t ) F t
    Where,
    F n MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGgbWaaSbaaSqaaiaad6gaaeqaaaaa@3AC1@
    The normal force
    μ ( F n MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGgbWaaSbaaSqaaiaad6gaaeqaaaaa@3AC1@ , F t MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGgbWaaSbaaSqaaiaad6gaaeqaaaaa@3AC1@ )
    Dynamic friction coefficient defined as:
    μ ( F n , F t ) = Fric f ff ( F n ) f fv ( v t )
    Where,
    v t
    Sliding velocity
    f f f and f f v
    Functions of fct_IDff and fct_IDfv
  4. Damping force, Fdamp is calculated as:
    F damp = f df ( F n ) ( Visc + f dv ( v n ) )
    Where,
    v n
    Penetration velocity
    f d f and f d v
    Functions of fct_IDdf and fct_IDdv