CNTSTB

Bulk Data Entry Defines parameters for stabilization control of surface-to-surface contact and large displacement node-to-surface contact.

A CNTSTB Bulk Data Entry should be referenced by a CNTSTB Subcase Information entry to be applied in a particular subcase globally.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CNTSTB ID   APSTB LMTGAP   S0 S1    
  SCALE TFRAC              
The following continuation line (beginning with the CNTINT flag) is used to define another set of stabilization parameters, which overrides the set of parameters above, and applied locally on a specific contact interface (CTID). It can be repeated as required.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
  CNTINT CTID APSTB LMTGAP   SO S1    
  SCALE TFRAC              
The continuation line can also be used to define a set of stabilization parameters for CGAP/CGAPG elements with gap property (PID).
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
  GAPINT PID APSTB LMTGAP   SO S1    
  SCALE TFRAC              

CNTINT and GAPINT continuation lines can coexist in one CNTSTB card. CTID and PID can be identical in one CNTSTB card, as well.

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CNTSTB 99   NO            
  CNTINT 51 YES            
    0.01              
  CNTINT 52 YES            
  10.0 0.01              
  GAPINT 52 YES            
  1.0E4 0.25              
  GAPINT 58 YES     1.0 0.001    
  1.0E4 0.05              

Definitions

Field Contents SI Unit Example
ID Each CNTSTB Bulk Data Entry should have a unique identification number.

No default (Integer > 0)

 
APSTB Head flag indicating if contact stabilization is activated.
YES
Contact stabilization effect is activated.
NO (Default)
Contact stabilization effect is deactivated.
Note: All the fields following APSTB should be blank, if APSTB is set to NO.
 
LMTGAP Contact opening threshold for stabilization. Stabilization becomes zero when contact opening is greater than or equal to this value.
blank (Default)
The threshold is calculated automatically based on characteristic edge lengths at the contact surfaces. The default threshold is 1.0 for the GAPINT continuation line.

Real > 0.0 - specified threshold value.

 
S0 Scale factor for stabilization coefficient at the start of a subcase.

Default = 1.0 (Real ≥ 0.0)

 
S1 Scale factor for stabilization coefficient at the end of a subcase.

Default = 0.0 (Real ≥ 0.0)

 
SCALE Stabilization coefficient scale factor.

Default = 1.0 (Real ≥ 0.0)

 
TFRAC Factor for scaling tangential stabilization with respect to normal stabilization.

Default = 0.1 (Real ≥ 0.0)

 
CNTINT Defines the start of a continuation line used to specify another set of stabilization parameters, which overrides the set of parameters defined above, for a specific contact interface (CTID). It can be repeated as required.  
CTID Contact interface identification number.

No default (Integer > 0)

 
GAPINT Defines the start of a continuation line used to specify another set of stabilization parameters, which overrides the set of parameters defined above, for specific CGAP/CGAPG elements (PID). It can be repeated as required.  
PID Gap property identification number

No default (Integer > 0)

 

Comments

  1. The CNTSTB Bulk Data Entry is selected by the CNTSTB Subcase Information Entry.
  2. When APSTB is YES, the contact normal stabilization stiffness K CSTB normal is calculated as:(1)
    K CSTB normal = { SCALE f ( t * ) K CREF if contact opening < LMTGAP 0 if contact opening LMTGAP

    Where, K C R E F MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGlbWaaSbaaSqaaiaadoeacaWGsbGaamyraiaadAeaaeqaaaaa @3D07@ is automatically calculated reference stiffness (10-5 times the contact penalty stiffness) for contact stabilization, and f ( t * ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGMbWaaeWaaeaacaWG0bWaaWbaaSqabeaacaGGQaaaaaGccaGL OaGaayzkaaaaaa@3D29@ is the time-dependent scale factor.

    For time, t MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWG0baaaa@39D0@ in a subcase, t * MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWG0bWaaWbaaSqabeaacaGGQaaaaaaa@3AAB@ is calculated as:(2)
    t * = ( t t 0 ) / ( t 1 t 0 )
    Where,
    t 0 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWG0bWaaSbaaSqaaiaaicdaaeqaaaaa@3AB6@
    Time at the start of the subcase
    t 1 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWG0bWaaSbaaSqaaiaaigdaaeqaaaaa@3AB7@
    Time at the end of the subcase

    f ( t * ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGMbWaaeWaaeaacaWG0bWaaWbaaSqabeaacaGGQaaaaaGccaGL OaGaayzkaaaaaa@3D29@ is calculated using S0 and S1 as f ( t * ) = S 0 ( t t * ) + S 1 t * MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKf MBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhi ov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8 qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9 q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaake aacaWGMbWaaeWaaeaacaWG0bWaaWbaaSqabeaacaGGQaaaaaGccaGL OaGaayzkaaGaeyypa0Jaam4uaiaaicdacqGHflY1daqadaqaaiaads hacqGHsislcaWG0bWaaWbaaSqabeaacaGGQaaaaaGccaGLOaGaayzk aaGaey4kaSIaam4uaiaaigdacqGHflY1caWG0bWaaWbaaSqabeaaca GGQaaaaaaa@4DEB@ .

  3. When APSTB is YES, the contact tangent stabilization stiffness K CSTB tangent is calculated as:(3)
    K CSTB tangent = TFRAC K CSTB normal
  4. The defaults and priority information in conjunction with PARAM,EXPERTNL,CNTSTB for different contact types are:
    Table 1. Contact Stabilization. Stabilization is not applicable to FREEZE or TIE Contact
      Model without LGDISP Analysis Model with LGDISP Analysis
    N2S S2S/CGAP/

    CGAPG

    N2S for LGDISP S2S/CGAP/

    CGAPG

    PARAM,EXPERTNL,CNTSTB Effective 2 Effective 1 Effective 1 Effective 1
    CNTSTB (Bulk card referenced by Subcase Entry) Ineffective Effective Effective Effective
    PARAM,EXPERTNL,CNTSTB + CNTSTB (Bulk card referenced by Subcase Entry) Stabilization with the PARAM is effective 2 For the subcase that references CNTSTB (Bulk Data), stabilization with the Bulk card is effective; For other subcases, stabilization with the PARAM is effective. 1 For the subcase that references CNTSTB (Bulk Data), stabilization with the Bulk card is effective; For other subcases, stabilization with the PARAM is effective. 1 For the subcase that references CNTSTB (Bulk Data), stabilization with the Bulk card is effective; For other subcases, stabilization with the PARAM is effective. 1
  5. When both CGAP/CGAPG elements and contact elements appear in a model together with CNTSTB applied globally, the global damping stabilization will not be applied on the CGAP/CGAPG elements, unless GAPINT is defined in CNTSTB card. When only CGAP/CGAPG elements appear in a model with CNTSTB applied globally, the global set of damping stabilization parameters will apply on the CGAP/CGAPG elements.
  6. This card is represented as a load collector in HyperMesh.

1 For Small Displacement S2S contacts/gaps and contacts/gaps in LGDISP, the stabilization activated with the PARAM is consistent with the stabilization activated with default settings of the CNTSTB Bulk Data Entry.
2 For Small Displacement N2S, the stabilization can only be activated with the PARAM, and both normal and tangential stabilizations are non-zero, if the PARAM is specified in the model.