GMATCH

Bulk Data Entry

GMATCH – Connect GRIDs between Two Subsets of a Model

Description

The GMATCH bulk data entry can be used to define equivalence for all degrees of freedom of grid points of two different subsets of without any requirement that these two subsets are closely located to one another.

Format 1 (Parts and Instances)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
GMATCH	ID	SETID1	SETID2	TOL	MOVE_FLAG

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
GMATCH	12	1202	1203	10.0

Field	Contents
ID	Identification number of the GMATCH Bulk Data Entry No default (Integer > 0)
SETIDi	Identification numbers of two SET’s of GRID’s to be matched. Each GRID from the first SET is matched to the closest GRID in the second SET. No default (Integer > 0)
TOL	Specifies the numeric value defining the maximum distance between two grid points to allow equivalence. All grid points in part SETID1 are considered during the search; if OptiStruct finds grid points in part SETID2 within the specified maximum distance (TOL), then such grid point pairs are equivalenced. No default (Real > 0.0)
MOVE_FLAG	Optional GRID SET ID. The grid point locations are used to restrict the search for matching nodes. These grids do not need to belong to either part “name_a” or part “name_b”. Default = NONE (NONE, UP, DOWN, or MID)

Comments

1.	Each GRID from the first SET will be matched to a maximum of one GRID from the second SET, but only if the distance between them is less than or equal to TOL.

2.	If the same GRID from SETID2 is matched to two different GRIDs from SETID1, then all three grids will be equivalenced. Such a situation is usually due to a modeling error and should be avoided by using two separate GMATCH entries with two separate grid sets.

3.	SETID1 and SETID2 should not have shared GRIDs.

By default, the equivalenced grids remain at their original locations (the gap between them may sometimes be larger than the element size). The optional MOVE_FLAG field allows you to move both grids to the same location, effectively filling the gap by stretching the elements on one or both sides. UP moves the grid from SETID1 to the location of its matching grid, DOWN moves the grid from SETID2, while MID, moves both grids toward the center. The move is performed after all pairs are identified.

5.	This entry is a connector, and can be used in a Parts and Instances model. SETID1/SETID2 refers to the Global part or can be fully qualified ID’s.

6.	In Parts and Instances modeling, the search for the nearest matching grid is performed after all parts are positioned in their final location.

7.	The search is performed only once. This entry is not suitable for subcase-specific modeling (that is, with LOCATE entries).

8.	This entry is similar to the CONNECT entry, however, it does not require that two sub-parts are positioned close to one another at the same location.