/RBE3

Block Format Keyword Defines the motion of a reference dependent node as the weighted average of the motions of sets of independent nodes.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/RBE3/rbe3_ID
rbe3_title
Node_IDr Trarotref N_set I_modif Iform
For each set with different weighting factors
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
WTi Trarot_Mi skew_IDi grnd_IDi

Definition

Field Contents SI Unit Example
rbe3_ID Interpolation constraint element identifier.

(Integer, maximum 10 digits)
rbe3_title Interpolation constraint element title.

(Character, maximum 100 characters)
Node_IDr Reference (dependent) node identifier.

(Integer)
Trarotref Code of DOF used for reference (dependent) node.
= 0
Free DOF
= 1
Fixed DOF

(6 Booleans)

Default (blank or 6 zeros), set on all DOF
N_set Number of different weighting factor and/or Trarot sets.

(Integer)
I_modif Modification of weighting factor flag. 4
= 1
Modification is automatic.
= 2
Forbidden modification.
= 3
Change all weighting factor to unity (1.0).

Default (blank or zero), set to 1 (Integer)
Iform Formulation flag.
= 1(Default)
Kinematic formulation with automatic switch to penalty formulation in case of incompatible kinematic conditions.
= 2
Kinematic formulation only.
= 3
Penalty formulation only.

(Integer)
WTi Weighing factor of set. i.

(Real)
Trarot_Mi Independent nodes' code of DOF used in interpolation of set i.

(6 Booleans)

Default (blank or 6 zeros), set on all DOF
skew_IDi Local skew identifier of set. i.

(Integer)
grnd_IDi Node group defining independent nodes of set i.

(Integer)

Codes for Translation and Rotation: Trarotref and Trarot_Mi

(1)-1 (1)-2 (1)-3 (1)-4 (1)-5 (1)-6 (1)-7 (1)-8 (1)-9 (1)-10
TX TY TZ ω X MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ ω Y MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ ω Z MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@

Definition

Field Contents SI Unit Example
TX Code for translation TX.
= 0
Free DOF
= 1
Fixed DOF

(Boolean)
TY Code for translation TY.
= 0
Free DOF
= 1
Fixed DOF

(Boolean)
TZ Code for translation TZ.
= 0
Free DOF
= 1
Fixed DOF

(Boolean)
ω X MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ Code for rotation ω X MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ .
= 0
Free DOF
= 1
Fixed DOF

(Boolean)
ω Y MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ Code for rotation ω Y MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ .
= 0
Free DOF
= 1
Fixed DOF

(Boolean)
ω Z MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ Code for rotation ω Z MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeaaciGaaiaabeqaamaabaabaaGcbaGaeqyYdC3aaS baaSqaaiaadIfaaeqaaaaa@38CA@ .
= 0
Free DOF
= 1
Fixed DOF

(Boolean)

Comments

  1. This is equivalent to OptiStruct's /RBE3, in which motion of a dependent node depends on the motion of a group of independent nodes with weighted average. It is similar to but more general than the kinematic condition /INTER/TYPE2 (which is limited by one dependent node to one independent segment (3 nodes or 4 nodes) and for all translations and/or all rotation components), the dependent rotation is computed as a function of translation and rotation of independent nodes, if all DOF are set on in Trarot_Mi.
  2. It is recommended that for most applications only the translation components be used for Trarot_Mi (Spotflag =1 in /INTER/TYPE2). An exception is the case where the independent nodes are co-linear and some of the dependent rotation components can not be determined. In this case, some rotational component should also be set on.
  3. The absolute values of the weighting factors are not important; it is the relative values from different sets that are important since these will be normalized.
  4. All DOF of the dependent node should be determinable.
    • If only translation components are used for Trarot_Mi and the independent nodes are quasi-co-linear, numerical instability might occur in explicit analysis to avoid this; Radioss by default, will modify the input weighting factors slightly (I_modif = 1). You can prevent this modification by setting I_modif = 2.
    • I_modif = 3 will give an equivalent behavior as /INTER/TYPE2 with Spotflag =1.
  5. With kinematic formulation (Iform=2), the following model building rule must be respected to solve correctly the kinematic conditions:

    /RBODY > /RBE3 > /RBE2 > /INTER/TYPE2.

  6. With Iform=0 or Iform=3, the /RBE3 linked to over constrained node automatically switches to penalty formulation to avoid any incompatible kinematic conditions.