cbdof

Mapdl.cbdof(fname1='', ext1='', fname2='', ext2='', kpos='', clab='', kshs='', tolout='', tolhgt='', tolthk='', **kwargs)

Activates cut-boundary interpolation (for submodeling).

APDL Command: CBDOF

Parameters
  • fname1 – File name and directory path (248 characters maximum, including directory) from which to read boundary node data. If no specified directory path exists, the path defaults to your working directory and you can use all 248 characters for the file name.

  • ext1 – Filename extension (eight-character maximum).

  • fname2 – File name and directory path (248 characters maximum, including directory) to which cut-boundary D commands are written. If no specified directory path exists, the path defaults to your working directory and you can use all 248 characters for the file name.

  • ext2 – Filename extension (eight-character maximum).

  • kpos

    Position on Fname2 to write block of D commands:

    0 - Beginning of file (overwrite existing file).

    1 - End of file (append to existing file).

  • clab – Label (eight characters maximum, including the colon) for this block of D commands on Fname2. his label is appended to the colon (:). Defaults to CBn, where n is the cumulative iteration number for the data set currently in the database. For imaginary data (see KIMG on the *SET command), Clab defaults to CIn.

  • kshs

    Shell-to-solid submodeling key:

    0 - Solid-to-solid or shell-to-shell submodel.

    1 - Shell-to-solid submodel.

  • tolout – Extrapolation tolerance about elements, based on a fraction of the element dimension. Submodel nodes outside the element by more than TOLOUT are not accepted as candidates for DOF extrapolation. Defaults to 0.5 (50 percent).

  • tolhgt – Height tolerance above or below shell elements, in units of length. Used only for shell-to-shell submodeling (KSHS = 0). Submodel nodes off the element surface by more than TOLHGT are not accepted as candidates for degree-of-freedom interpolation or extrapolation. Defaults to 0.0001 times the maximum element dimension.

  • tolthk – Height tolerance above or below shell elements, based on a fraction of the shell element thickness. Used only for shell-to-solid submodeling (KSHS = 1). Submodel nodes off the element surface by more than TOLTHK are not accepted as candidates for DOF interpolation or extrapolation. Defaults to 0.1 times the average shell thickness.

Notes

File Fname1 should contain a node list for which boundary conditions are to be interpolated (NWRITE). File Fname2 is created to contain interpolated boundary conditions written as a block of D commands.

Boundary conditions are written for the active degree-of-freedom set for the element from which interpolation is performed. Interpolation occurs on the selected set of elements. The block of D commands begins with an identifying colon label and ends with a /EOF command. The colon label is of the form :Clab (described above).

Interpolation from multiple results sets can be performed by looping through the results file in a user-defined macro. Additional blocks can be appended to Fname2 by using KPOS and unique colon labels. To read the block of commands, issue the /INPUT command with the appropriate colon label.

If the model has coincident (or very close) nodes, the CBDOF must be applied to each part of the model separately to ensure that the mapping of the nodes is correct. For example, if nodes belonging to two adjacent parts linked by springs are coincident, the operation should be performed on each part of the model separately.

Resume the coarse model database at the beginning of the cut-boundary procedure. The database should have been saved after the first coarse model solution, as the number of nodes in the database and the results file must match, and internal nodes are sometimes created during the solution.

Caution: Relaxing the TOLHGT or TOLTHK tolerances to allow submodel nodes to be “found” can produce poor submodel results.