DSHAPE

Bulk Data Entry

DSHAPE – Design Variable for Free-Shape Optimization

Description

Defines parameters for the generation of free-shape design variables.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
DSHAPE	ID
	PERT	DTYPE	MVFACTOR	NSMOOTH	MXSHRK	MXGROW	SMETHOD	NTRANS
	GRID	GMETH	GSETID1/ GID1	GID2/GSETID2	GID3/GSETID3	GID4/GSETID4	GID5/GSETID5	GID6/GSETID6
		GID7/GSETID7	GID8/GSETID8	…	…
	PATRN	TYP	AID/XA	YA	ZA	FID/XF	YF	ZF
	DRAW	DTYP	DAID/XDA	YDA	ZDA	DFID/XDF	YDF	ZDF
		DRAFT
	EXTR	ECID	XE	YE	ZE
	GRIDCON	GCMETH	GCSETID1 / GDID1	CTYPE1	CID1	X1	Y1	Z1
		GCMETH	GCSETID2 / GDID2	CTYPE2	CID2	X2	Y2	Z2
		…	…
	SDCON	SDCID1	XL1	XU1	YL1	YU1	ZL1	ZU1
		SDCID2	XL2	XU2	YL2	YU2	ZL2	ZU2
		…	…
	BMESH	BMID
	FSSPLIT	SPLIT

Field	Contents
ID	Each DSHAPE card must have a unique ID. No default (Integer > 0)
PERT	Indicates perturbation information is to follow.
DTYPE	Specifies the direction type for the free-shape variation. GROW – grids cannot move inside of the initial part boundary. SHRINK – grids cannot move outside of the initial part boundary. BOTH – grids are unconstrained. Default = BOTH
MVFACTOR	Initial limit on the movement factor of the design grids. The unit of MVFACTOR is the average mesh size of meshes adjacent to grids defined after GRID. Only the initial value of this limit can be set. The values in subsequent optimization iterations are automatically adjusted to enhance to enhance iterative stability and convergence speed; however, they will never be greater than the initial limit. Default = 0.5 (Real > 0.0)
NSMOOTH	Number of grids layers NSMOOTH. Default = 10 (Integer)
MXSHRK	Maximum shrinking distance. No default
MXGROW	Maximum growing distance. No default
SMETHOD	Mesh smoothing method. Default = 1 (1 or 2) Method 1 is faster than method 2, but method 2 is more robust in avoiding mesh distortion.
NTRANS	Number of design grid layers in the transition zone to non-design area, where additional treatment will be applied to produce smooth transition (Comment 2). Default = 0 (Integer > 0)
GRID	Indicates that a list of grid IDs or grid sets is to follow (depending on the value of the GMETH field). These grids are design variables for the free-shape optimization.
GMETH	Field indicating whether grids are to be defined by a list of grid IDs or as Grid SET references. If ID is specified, the following fields on this continuation line are grid point IDs. If SET is specified, the following fields on this continuation line are grid SET id’s. Default = ID (SET or ID)
GID#	Grid identification numbers. List of grids for which this DSHAPE card is defined (only valid if GMETH field is set to ID). No default (Integer > 0)
GSETID#	Grid SET identification number. A grid set containing design grids for free-shape optimization (only valid if GMETH field is set to SET). No default (Integer > 0)
PATRN	Indicates that variable pattern grouping is active. Indicates that information about the pattern group will follow.
TYP	Type of variable pattern grouping. Required if any symmetry or variable pattern grouping is desired. Only 1-plane symmetry (TYP=10) is currently supported. Default = 0 (0 or 10)
AID/XA, YA, ZA	Variable pattern grouping anchor point. These fields define a point that determines how grids are grouped into variables (Comment 1). The X, Y, and Z values are in the global coordinate system. You may put a grid ID in the AID/XA field to define the anchor point. Default = origin (Real in all three fields or Integer in AID/XA field)
FID/XF, YF, ZF	Direction of first vector for variable pattern grouping. These fields define an xyz vector which determines how grids are grouped into variables (Comment 1). The X, Y, and Z values are in the global coordinate system. If FID is defined, it defines a vector pointing from grid AID or point (XA, YA, and ZA) to grid FID. If XF, YF, ZF are defined, it defines a vector pointing from point (XA, YA, and ZA) to point (XA+XF,YA+YF,ZA+ZF). (XA, YA, and ZA) are coordinates of the anchor point defined by AID or XA, YA, and ZA. If all fields are blank and the TYP field is not blank or zero, OptiStruct gives an error. No default
DRAW	Indicates that casting constraints are being applied. Indicates that draw direction information is to follow. Only valid for design grids on solid elements.
DTYP	Type of draw direction constraint to be used. SINGLE indicates that a single die will be used, the die being withdrawn in the given draw direction. Only SINGLE is available in 9.0.
DAID/XDA, YDA, ZDA	Draw direction anchor point. These fields define the anchor point for draw direction of the casting. The point may be defined by entering a grid ID in the DAID field or by entering X, Y, and Z coordinates in the XDA, YDA, and ZDA fields, these coordinates will be in the basic coordinate system. Default = origin (Real in all three fields or Integer in first field)
DFID/XDF, YDF, ZDF	Direction of vector for draw direction definition. These fields define a point. The vector goes from the anchor point to this point. The point may be defined by entering a grid ID in the DFID field or by entering X, Y, and Z coordinates in the XDF, YDF, and ZDF fields, these coordinates will be in the basic coordinate system. No default (Real in all three fields or Integer in first field)
DRAFT	Draft angle in degrees. See comment 5. Default = 0.0 (0.0 < Real < 90.0)
SDCON#	Indicates that side constraints are being applied.
SDCID#	The ID of a coordinate system which the following XL#, XU#, YL#, YU#, ZL#, or ZU# components are resolved in.
XL#, XU#, YL#, YU#, ZL#, ZU#	Side constraints defined by lower and upper bounds of coordinates, which restrict the moving space of the design grids. Any of the six fields could be blank, which means the corresponding coordinate is not constrained.
EXTR	Indicates that extrusion constraints are being applied. Indicates that extrusion information is to follow. Only valid for design grids on solid elements.
ECID	The ID of a coordinate system which the following X, Y, and Z components are resolved in. Default = 0 (Integer > 0) For Free-Shape 9.0, only consider two simple extrusion paths: Line and Circle. Line - ECID is a rectangular system. Circle - ECID is a cylindrical system.
XE, YE, ZE	When ECID is a rectangular system ID, X, Y, and Z are components of a vector under system EID, which define the extrusion path.
GRIDCON	Indicates that a list of grids with associated constraints are to follow. Note: Grids within the smoothing zone (defined by NSMOOTH) will move during Free-shape optimization to avoid mesh distortion without changing the shape of the model. Users can also constrain the movement of these grids by GRIDCON even if they are not defined after GRID.
GCMETH	Indicates that a list of grids is to be defined by a list of grid IDs or a single SET reference. Default = ID (SET or ID)
GCSETID#	Grid SET identification numbers. IDs of certain grid SETs which are constrained to move in a predefined manner. No default (Integer > 0)
GDID#	IDs of certain grids which are constrained to move in a predefined manner. No default (Integer > 0, ID must also be present in the list following the GRID flag)
CTYPE#	Specifies the type of constraint applied to the grid GDID#. FIXED – grid cannot move due to free-shape optimization. VECTOR – grid is forced to move along the vector defined by the following fields. PLANAR – grid is forced to remain on a plane for which the following fields define the normal direction. No default (FIXED, VECTOR or PLANAR)
CID#	The ID of a coordinate system which the following X, Y, and Z components are resolved in. Default = 0 (Integer > 0)
X#, Y#, Z#	X, Y, and Z components of a vector, which either defines the direction in which the grid GDID# is constrained to move, or the normal of a plane on which the grid GDID# is constrained to remain. Default = 0.0 (Real)
BMESH	Indicates that a BMFACE ID is to follow.
BMID	The BMFACE ID which defines a list of QUADs and/or TRIAs which define a barrier that the design surface will not penetrate during shape optimization.
FSSPLIT	Indicates that the design grids in the Free-Shape design space referenced by DSHAPE are split into multiple DSHAPE’s, based on their normal orientation.
SPLIT	Controls the splitting of the design grids for this DSHAPE entry. YES: The design grids are split based on their normal orientation. NO: The design grids are not split. Default = NO (YES or NO)

Comments

1.	For a single plane of symmetry (TYP = 10), the plane is defined normal to the first vector and is located at the anchor node.

The NTRANS option allows you to achieve a smooth transition between design and non-design regions. This additional smoothness, however, comes with an inherent cost of a reduction in design flexibility. NTRANS improves design smoothness across the transition zone between design and non-design regions at the expense of design flexibility.

For detailed information illustrating the working mechanism of NTRANS, refer to Defining Free-shape Design Regions in the User’s Guide.

3.	The draft angle can be specified in degrees via the DRAFT field, as illustrated in the figure below. Geometric constraints (GRIDCON and SDCON) may not be satisfied when the draft angle is activated:

draft_angle

4.	This card is represented as an optimization design variable in HyperMesh.