PBUSHT

Bulk Data Entry Defines property values for a generalized spring and damper structural element.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
PBUSHT PID TYPE TID1 TID2 TID3 TID4 TID5 TID6  
    TYPE TID1 TID2 TID3 TID4 TID5 TID6  
    TYPE TID1 TID2 TID3 TID4 TID5 TID6  
    TYPE TID1 TID2 TID3 TID4 TID5 TID6  
    etc etc            

Definitions

Field Contents SI Unit Example
PID Property identification number. Must match with a PID of a PBUSH Bulk Data Entry.

No default (Integer > 0)

  
TYPE Identifies what the following six fields referenced. Can be defined in any order but may only appear once per PBUSH definition. 3 5 6
K
The following six fields are stiffness versus frequency table references for dofs 1 through 6, respectively.
B
The following six fields are viscous damping versus frequency table references for dofs 1 through 6, respectively.
GE
The following six fields are structural damping versus frequency table references for dofs 1 through 6, respectively.
M
The following six fields are directional mass versus frequency table references for dofs 1 through 6, respectively.
KN
The following six fields are force versus deflection table references for dofs 1 through 6, respectively.
Or,
KSCALE
The following six fields are stiffness scale factors versus frequency table references for dofs 1 through 6, respectively.
BSCALE
The following six fields are viscous damping scale factors versus frequency table references for dofs 1 through 6, respectively.
GESCALE
The following six fields are structural damping scale factors versus frequency table references for dofs 1 through 6, respectively.
MSCALE
The following six fields are directional mass scale factors versus frequency table references for dofs 1 through 6, respectively.
Or,
ANGLE
The following six fields are angles versus frequency table references for dofs 1 through 6, respectively.
KMAG
The following six fields are magnitude of stiffness versus frequency table references for dofs 1 through 6, respectively.

No default

 
TID# A TABLED# entry identification number. The type of the referenced table is defined by the TYPE keyword given on the same line. The six references on each line represent the 6 degrees-of-freedom in sequence from 1 through 6.

Default = 0 (Integer ≥ 0)

  

Comments

  1. The K, B, GE, and M fields are associated with the same entries on the PBUSH entry.
  2. PBUSHT may only be referenced by CBUSH elements in the residual structure which do not attach to any omitted degrees-of-freedom.
  3. TYPE=K/KSCALE, B/BSCALE, GE/GESCALE, M/MSCALE and KMAG/ANGLE are allowed for frequency response analysis only, while TYPE=KN is allowed only for nonlinear analysis. In Modal Frequency Response Analysis, the frequency-dependency is only used in the frequency response part of the solution, not in the modal analysis part of the solution.

    For TYPE=KN, Tension is U > 0 and Compression is U < 0 where U = U(GB) - U(GA) in CBUSH element coordinate system: GA/GB are grid points on CBUSH.

  4. For backward compatibility with Nastran, if ONLY the dof1 field for the GE line (line where TYPE=GE) is specified on ALL PBUSHT entries and the other dofs for the GE line are blank on ALL PBUSH entries, then a single structural damping table for each PBUSHT applied to all defined dofs on the K line for each PBUSH is assumed. If ANY PBUSHT entry has a dof field other than dof1 for the GE line specified, then the GE fields are considered variable on ALL PBUSH and PBUSHT entries.
  5. Rotational stiffness values are input based on rotations defined in Radians.
  6. KMAG/ANGLE continuation line only affects stiffness (K) and damping (GE) values.

    If ANGLE and KMAG continuation lines on PBUSHT are both defined, then for a particular degree of freedom, after table lookup, the value of frequency-dependent stiffness is equal to KMAG*cos(angle) and GE is equal to tan (ANGLE). Where, KMAG and ANGLE are the magnitude of stiffness and angle values looked up from corresponding dof tables in the KMAG and ANGLE continuation lines. ANGLE is in degrees.

    If ANGLE is present, but KMAG continuation line is not defined, then OptiStruct will error out.

  7. This card is represented as a property in HyperMesh.