/CLUSTER

Block Format Keyword Describes an assembly of brick or spring elements for post-processing and failure control.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/CLUSTER/ELEM_TYPE/cluster_ID/unit_ID
cluster_title
group_ID skew_ID Ifail              
Fn_fail1 a1 b1        
Fs_fail a2 b2        
Mt_fail a3 b3        
Mb_fail a4 b4        

Definition

Field Contents SI Unit Example
ELEM_TYPE Cluster element type.
BRICK
Cluster of brick elements
SPRING
Cluster of spring elements
 
cluster_ID Cluster identifier.

(Integer, maximum 10 digits)

 
unit_ID Unit Identifier.

(Integer, maximum 10 digits)

 
cluster_title Cluster block title.

(Character, maximum 100 characters)

 
group_ID Element group identifier.

(Integer)

 
skew_ID Skew identifier.

(Integer)

 
Ifail Failure model option.
= 0 (Default)
No global failure criterion.
= 1
Unidirectional failure, element is deleted if force or moment in one direction reaches the limit value.
= 2
Unidirectional failure, element is deleted if forces and moments in all directions reach the limit values.
= 3
Multi-directional failure. 8

(Integer)

 
Fn_fail Failure force in normal direction (tension).

Default = 1.0e30 (Real)

[ N ]
Fs_fail Failure force in tangent direction (shear).

Default = 1.0e30 (Real)

[ N ]
Mt_fail Failure moment in normal direction (torsion).

Default = 1.0e30 (Real)

[ N m ] MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaaci GGobGaeyyXICTaciyBaaGaay5waiaaw2faaaaa@3BFA@
Mb_fail Failure moment in tangent direction (bending).

Default = 1.0e30 (Real)

[ N m ] MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaaci GGobGaeyyXICTaciyBaaGaay5waiaaw2faaaaa@3BFA@
a1 - a4 Multi-directional failure scale factors (only used if Ifail =3).

Default = 1.0 (Real)

 
b1 - b4 Multi-directional failure exponents (only used if Ifail =3).

Default = 1.0 (Real)

 

Comments

  1. The cluster of elements are used for connection (spotweld, welding line, glue, and so on).
  2. The cluster of elements may only be defined with groups of solid (8 node bricks) or spring elements.
  3. For bricks, cluster of elements works with LAW59 and LAW83 only. Solid elements of cluster should be interconnected.
  4. For springs, cluster of elements works with TYPE13.
  5. The number of elements in cluster group is limited to 500.
  6. All cluster elements must have the same orientation (Z local coordinate for solids, X local coordinate for springs, or direction from first to second node).
  7. Only one layer of element in the normal (thickness direction) is allowed to define a cluster.
  8. When force/moment failure criterion is reached (see cluster failure definition below), then all elements in the cluster are deleted. Force and moment are always calculated in local cluster coordinate system or in skew system specified in /CLUSTER card.
  9. Cluster elements may have material referring to /FAIL/CONNECT or /FAIL/SNCONNECT, or to a failure spring property. These criteria are independent from the cluster failure criterion defined in /CLUSTER. Single elements may be deleted according to these failure criteria, but this will not affect the cluster failure.
  10. Failure criterion FAIL is calculated, as follows:
    Unidirectional local, Ifail=1:(1)
    FAIL=max( | Fn Fn_fail |,| Fs Fs_fail |,| Mt Mt_fail |,| Mb Mb_fail | ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOraiaadg eacaWGjbGaamitaiabg2da9iGac2gacaGGHbGaaiiEamaabmaabaWa aqWaaeaadaWcaaqaaiaadAeacaWGUbaabaGaamOraiaad6gacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaadAeacaWGZbaabaGaamOraiaadohacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaad2eacaWG0baabaGaamytaiaadshacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaad2eacaWGIbaabaGaamytaiaadkgacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoaaiaawIca caGLPaaaaaa@6DB8@
    Unidirectional general, Ifail=2:(2)
    FAIL=min( | Fn Fn_fail |,| Fs Fs_fail |,| Mt Mt_fail |,| Mb Mb_fail | ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOraiaadg eacaWGjbGaamitaiabg2da9iGac2gacaGGPbGaaiOBamaabmaabaWa aqWaaeaadaWcaaqaaiaadAeacaWGUbaabaGaamOraiaad6gacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaadAeacaWGZbaabaGaamOraiaadohacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaad2eacaWG0baabaGaamytaiaadshacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoacaGGSaWa aqWaaeaadaWcaaqaaiaad2eacaWGIbaabaGaamytaiaadkgacaGGFb GaamOzaiaadggacaWGPbGaamiBaaaaaiaawEa7caGLiWoaaiaawIca caGLPaaaaaa@6DB6@
    Multi-directional, Ifail=3:(3)
    FAIL= a 1 ( Fn Fn_fail ) b 1 + a 2 ( Fs Fs_fail ) b 2 + a 3 ( Mt Mt_fail ) b 3 + a 4 ( Mb Mb_fail ) b 4 >1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOraiaadg eacaWGjbGaamitaiabg2da9iaadggadaWgaaWcbaGaaGymaaqabaGc daqadaqaamaalaaabaGaamOraiaad6gaaeaacaWGgbGaamOBaiaac+ facaWGMbGaamyyaiaadMgacaWGSbaaaaGaayjkaiaawMcaamaaCaaa leqabaGaamOyamaaBaaameaacaaIXaaabeaaaaGccqGHRaWkcaWGHb WaaSbaaSqaaiaaikdaaeqaaOWaaeWaaeaadaWcaaqaaiaadAeacaWG ZbaabaGaamOraiaadohacaGGFbGaamOzaiaadggacaWGPbGaamiBaa aaaiaawIcacaGLPaaadaahaaWcbeqaaiaadkgadaWgaaadbaGaaGOm aaqabaaaaOGaey4kaSIaamyyamaaBaaaleaacaaIZaaabeaakmaabm aabaWaaSaaaeaacaWGnbGaamiDaaqaaiaad2eacaWG0bGaai4xaiaa dAgacaWGHbGaamyAaiaadYgaaaaacaGLOaGaayzkaaWaaWbaaSqabe aacaWGIbWaaSbaaWqaaiaaiodaaeqaaaaakiabgUcaRiaadggadaWg aaWcbaGaaGinaaqabaGcdaqadaqaamaalaaabaGaamytaiaadkgaae aacaWGnbGaamOyaiaac+facaWGMbGaamyyaiaadMgacaWGSbaaaaGa ayjkaiaawMcaamaaCaaaleqabaGaamOyamaaBaaameaacaaI0aaabe aaaaGccqGH+aGpcaaIXaaaaa@74D0@
  11. Local coordinate system is defined as:
    • If skew_ID > 0, the skew Z-axis defines normal direction in the local coordinate system, tangent plane will be defined by skew X and Y axis.
    • If skew_ID = 0, the normal direction in the local coordinate system is defined by the vector between geometrical centers of nodes on bottom and top side.
  12. Available post-processing options:
    • /ANIM/VECT/CLUST/FORCE - force vector in global coordinates
    • /ANIM/VECT/CLUST/MOM - moment vector in global coordinates
    • /TH/CLUSTER - forces and moments in global or local coordinates
  13. Output for TH: Forces and moments in global and local coordinate system, failure criterion FAIL.
  14. True thickness parameter which accounts for virtual height of the cluster in /PROP/CONNECT is active only when skew_ID = 0.