DSIZE
Bulk Data Entry Defines parameters for the generation of free-size design variables.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
DSIZE | ID | PTYPE | PID1 | PID2 | PID3 | PID4 | PID5 | PID6 | |
PID7 | etc | etc | etc | etc | etc | etc |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
THICK | T0 | T1 | TG | TGX | TGY | TGZ |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
STRESS | UBOUND |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MEMBSIZ | MINDIM |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
+ | COMP | LAMTHK | LTMIN | LTMAX | LTSET | LTEXC | |||
+ | COMP | PLYTHK | PTGRP | PTMIN | PTMAX | PTOPT | PTSET | PTEXC | |
+ | COMP | PLYPCT | PPGRP | PPMIN | PPMAX | PPOPT | PPSET | PPEXC | |
+ | COMP | PLYMAN | PMGRP | PMMAN | PMDIS | PMOPT | PMSET | PMEXC | |
+ | COMP | BALANCE | BGRP1 | BGRP2 | BOPT | ||||
+ | COMP | CONST | CGRP | CTHICK | COPT | ||||
+ | COMP | PLYDRP | PDGRIP | PDTYP | PDMAX | PDOPT | PDSET | PDEXC | |
+ | PDDEF | PDX | PDY | PDZ |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
PATRN | TYP | AID/ XA |
YA | ZA | FID/ XF |
YF | ZF | ||
UCYC | SID/ XS |
YS | ZS |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MAIN | |||||||||
COORD | CID | CAID/ XCA |
YCA | ZCA | CFID/ XCF |
YCF | ZCF | ||
CSID/ XCS |
YCS | ZCS | CTID/ XCT |
YCT | ZCT |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
SECOND | DSIZE_ID | SX | SY | SZ | |||||
COORD | CID | CAID/ XCA |
YCA | ZCA | CFID/ XCF |
YCF | ZCF | ||
CSID/XCS | YCS | ZCS | CTID/ XCT |
YCT | ZCT |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
FATIGUE | FTYPE | FBOUND |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
GROUP | EG1 | EG2 | EG3 | EG4 | EG5 | EG6 | |||
EG7 | EG8 | EG9 | etc | etc | etc | etc |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
GROUP | EG1 | THRU | EG2 |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
GROUP | AUTO | SIZE | |||||||
EG1 | EG2 | EG3 | etc | etc | etc | etc |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
TAPE | LTAPE | WTAPE | OFFSET |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATINIT | VALUE |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
DRAW | DTYP | DAID/ XDA |
YDA | ZDA | DFID/ XDF |
YDF | ZDF | ||
ANGLE |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
ID | Each
DSIZE card must have a unique ID. No default (Integer > 0) |
|
PTYPE | Property type for which
DSIZE card is defined.
No default |
|
PID# | Property identification
numbers. List of PTYPE properties for which this
DSIZE card is defined. Refer to Comment 16 for some limitations when PTYPE=SET. No default (Integer > 0) |
|
THICK | Indicates that minimum and possibly maximum thickness values, or thickness gradient information are to follow. | |
T0 | Minimum thickness. For PTYPE = PSHELL or SET, this refers to the minimum thickness of the shell. If a value is not entered for T0, the T0 value on the PSHELL card is used. If T0 is not defined on the PSHELL card, then T0=0.0 is assumed. This option does not apply for PTYPE = PCOMP, PCOMPG, or STACK. Default = blank (Real ≥ 0.0) |
|
T1 | Maximum thickness. For PTYPE = PSHELL or SET, this refers to the maximum thickness of the shell. If T1 is defined, it disregards the thickness (T) on PSHELL and/or the nodal thickness (Ti) of the element. If T1 is not defined, the T value on the PSHELL card is used. This option does not apply for PTYPE = PCOMP, PCOMPG, or STACK. Default = blank (Real ≥ T0) |
|
TG | Specifies the maximum
thickness gradient. Default = blank (Real > 0.0) |
|
TGX, TGY, TGZ | Defines a vector that
specifies the thickness gradient direction (optional). Default = blank (Real) |
|
STRESS | Indicates that von Mises stress constraints are active and that an upper bound value for the stress is to follow. 4 | |
UBOUND | Upper bound constraint on
von Mises stress. No default (Real > 0.0) |
|
MEMBSIZ | Indicates that member size control is active for the properties listed. Indicates that MINDIM is to follow. | |
MINDIM | Specifies the minimum
diameter of members formed. This command is used to eliminate small
members. It also eliminates checkerboard results. 3 Default = No minimum member size control (Real > 0.0) |
|
COMP | Indicates that composite manufacturing constraints are applied. Indicates that information about manufacturing constraints is to follow. 5 | |
LAMTHK | Indicates that laminate thickness constraints are applied. Multiple LAMTHK constraints are allowed. 5 | |
LTMIN | Minimum laminate thickness
for the LAMTHK constraint. Default = blank (Real > 0.0) |
|
LTMAX | Maximum laminate thickness
for the LAMTHK constraint. Default = blank (Real > 0.0 and > LTMIN) |
|
LTSET | Set ID of elements to which the LAMTHK constraint is applied. | |
LTEXC | Exclusion flag indicating
that certain plies are excluded from the LAMTHK
constraint. Supported options are:
|
|
PLYTHK | Indicates that ply thickness constraints are applied. Multiple PLYTHK constraints are allowed. | |
PTGRP | Ply orientation in
degrees, ply sets or ply IDs, to which the PLYTHK
constraint is applied, depending on the PTOPT
selection. No default (Real or Integer) |
|
PTMIN | Minimum thickness for the
PLYTHK constraint. Default = blank (Real > 0.0) |
|
PTMAX | Maximum thickness for the
PLYTHK constraint. Default = blank (Real > 0.0 and > PTMIN) |
|
PTOPT | Ply selection options for
the PLYTHK constraint. Plies can be selected
based on:
|
|
PTSET | Set ID of elements to which the PLYTHK constraint is applied. | |
PTEXC | Exclusion flag indicating
that certain plies are excluded from the PLYTHK
constraint. Supported options are:
|
|
PLYPCT | Indicates that ply thickness percentage constraints are applied. Multiple PLYPCT constraints are allowed. | |
PPGRP | Ply orientation in
degrees, ply sets or ply IDs, to which the PLYPCT
constraint is applied, depending on the PPOPT
selection. No default (Real or Integer) |
|
PPMIN | Minimum percentage
thickness for the PLYPCT constraint. Default = blank (Real > 0.0 and < 1.0) |
|
PPMAX | Maximum percentage
thickness for the PLYPCT constraint. Default = blank (Real > 0.0, < 1.0 and > PPMIN) |
|
PPOPT | Ply selection options for
the PLYPCT constraint. Plies can be selected
based on:
|
|
PPSET | Set ID of elements to which the PLYPCT constraint is applied. | |
PPEXC | Exclusion flag indicating
that certain plies are excluded from the PLYPCT
constraint. Support options are:
|
|
PLYMAN | Indicates that manufacturable ply thickness constraints are applied. Multiple PLYMAN constraints are allowed. | |
PMGRP | Ply orientation in
degrees, ply sets or ply IDs, to which the PLYMAN
constraint is applied, depending on the PMOPT
selection. No default (Real or Integer) |
|
PMMAN | Manufacturable ply
thickness. 15 Default = blank (Real > 0.0) |
|
PMDIS | Defines the thickness step
for discrete design variable definition. 15 Default = blank (Real > 0.0) |
|
PMOPT | Ply selection options for
the PLYMAN constraint. Plies can be selected
based on:
|
|
PMSET | Set ID of elements to which the PLYMAN constraint is applied. | |
PMEXC | Exclusion flag indicating
that certain plies are excluded from the PLYMAN
constraint. Support options are:
|
|
BALANCE | Indicates that a balancing constraint is applied. Multiple BALANCE constraints are allowed. | |
BGRP1 | First ply orientation in
degrees, ply sets or ply IDs, to which the
BALANCE constraint is applied, depending on
the BOPT selection. No default (Real or Integer) |
|
BGRP2 | Second ply orientation in
degrees, ply sets or ply IDs, to which the
BALANCE constraint is applied, depending on
the BOPT selection. No default (Real or Integer) |
|
BOPT | Ply selection options for
the BALANCE constraint. Plies can be selected
based on:
|
|
CONST | Indicates that a constant thickness constraint is applied. Multiple CONST constraints are allowed. | |
CGRP | Ply orientation in
degrees, ply sets or ply IDs, to which the CONST
constraint is applied, depending on the COPT
selection. No default (Real or Integer) |
|
CTHICK | Constant ply thickness for
the CONST constraint. No default (Real > 0.0) |
|
COPT | Ply selection options for
the CONST constraint. Plies can be selected based
on:
|
|
PLYDRP | Indicates that ply drop-off constraints are applied. Multiple PLYDRP constraints are allowed. | |
PDGRP | Ply orientation in
degrees, ply sets or ply IDs, to which the PLYDRP
constraint is applied, depending on the PDOPT
selection. No default (Real or Integer) |
|
PDTYP | Specifies the type of the
drop-off constraint as: 10
|
|
PDMAX | Maximum allowed drop-off
for the PLYDRP constraint. No default (Real > 0) |
|
PDOPT | Ply selection options for
the PLYDRP constraint. Plies can be selected
based on:
|
|
PDSET | Set IDs of elements to which the PLYDRP constraint is applied. | |
PDEXC | Exclusion flag indicates
that certain plies are excluded from the PLYDRP
constraint. Supported options are:
|
|
PDDEF | Optional definition to fine-tune the drop-off constraint. Currently only DIRECT is available to request directional drop-off, in which case PDX, PDY and PDZ specify the drop-off direction. 11 | |
PDX, PDY, PDZ | Used to specify the drop-off direction when DIRECT is input in the PDDEF field. 11 | |
PATRN | Indicates that pattern grouping is active for the properties listed. Indicates that information for pattern grouping is to follow. | |
TYP | Pattern grouping type
requested. 1 Default = No pattern grouping (1, 2, 3, 9, 10, 11, 20 or 21) |
|
AID/XA, YA, ZA | Anchor point for pattern
grouping. The point may be defined by entering a grid ID in the
AID field or by entering X, Y, and Z
coordinates in the XA, YA, and
ZA fields. These coordinates will be in the
basic coordinate system. 1 Default = origin (Real in all three fields or Integer in first field) |
|
FID/XF, YF, ZF | First point for pattern
grouping. The point may be defined by entering a grid ID in the
FID field or by entering X, Y, and Z
coordinates in the XF, YF, and
ZF fields. These coordinates will be in the
basic coordinate system. 1 No default (Real in all three fields or Integer in the first field) |
|
UCYC | Number of cyclical
repetitions for cyclical symmetry. This field defines the number of
radial "wedges" for cyclical symmetry. The angle of each wedge is
computed as 360.0/UCYC. 1 Default = blank (Integer > 0 or blank) |
|
SID/XS, YS, ZS | Second point for pattern
grouping. The point may be defined by entering a grid ID in the
SID field or by entering X, Y, and Z
coordinates in the XS, YS, and
ZS fields. These coordinates will be in the
basic coordinate system. 1 No default (Real in all three fields or Integer in first field) |
|
MAIN | Indicates that this design variable may be used as a main pattern for pattern repetition. 2 | |
SECOND | Indicates that this design variable is secondary to the main pattern definition referenced by the following DSIZE_ID entry. 2 | |
DSIZE_ID | DSIZE
identification number for a main pattern definition. No default (Integer > 0) |
|
SX, SY, SZ | Scale factors for pattern
repetition, in X, Y, and Z directions, respectively. 2 Default = 1.0 (Real > 0.0) |
|
COORD | Indicates information regarding the coordinate system for pattern repetition is to follow. This is required if either MAIN or SECOND flags are present. | |
CID | Coordinate system ID for a
rectangular coordinate system that may be used as the pattern
repetition coordinate system. 2 Default = 0 (Integer > 0) |
|
CAID/XCA, YCA, ZCA | Anchor point for pattern
repetition coordinate system. The point may be defined by entering a
grid ID in the CAID field or by entering X, Y,
and Z coordinates in the XCA,
YCA, and ZCA fields. These
coordinates will be in the basic coordinate system. 2 No default (Real in all three fields or Integer in the first field) |
|
CFID/XCF, YCF, ZCF | First point for pattern
repetition coordinate system. The point may be defined by entering a
grid ID in the CFID field or by entering X, Y,
and Z coordinates in the XCF,
YCF, and ZCF fields. These
coordinates will be in the basic coordinate system. 2 No default (Real in all three fields or Integer in the first field) |
|
CSID/XCS, YCS, ZCS | Second point for pattern
repetition coordinate system. The point may be defined by entering a
grid ID in the CSID field or by entering X, Y,
and Z coordinates in the XCS,
YCS, and ZCS fields. These
coordinates will be in the basic coordinate system. 2 No default (Real in all three fields or Integer in the first field) |
|
CTID/XCT, YCT, ZCT | Third point for pattern
repetition coordinate system. The point may be defined by entering a
grid ID in the CTID field or by entering X, Y,
and Z coordinates in the XCT,
YCT, and ZCT fields. These
coordinates will be in the basic coordinate system. 2 No default (Real in all three fields or Integer in the first field) |
|
FATIGUE | Indicates that fatigue constraints are active and their definition is to follow. | |
FTYPE | Fatigue constraint
type:
|
|
FBOUND | Specifies the bound
value. If FTYPE is DAMAGE, FBOUND will be the upper bound of fatigue damage. If FTYPE is LIFE or FOS, FBOUND will be the lower bound of fatigue life (LIFE) or Factor of Safety (FOS), respectively. No default (Real) |
|
GROUP | Specifies the definition of zone based free-sizing optimization. Indicates that element group IDs will follow. | |
EG# | Element group numbers.
Element groups are created through element sets (Format 1). 6 No default (Integer > 0) |
|
THRU | This keyword can be used
in the optional alternate format to define zone based free-sizing
optimization. This keyword is used for ID range definition to indicate that all ID's between the preceding ID (EG1) and the following ID (EG2) are to be included in the set. |
|
AUTO | Automatic creation of
Element groups for zone-based free-sizing optimization is activated
(Format 2). The element groups are automatically created based on
the SIZE field. No default (should be set to AUTO for Format 2) |
|
SIZE | Specifies the size of the
patch to automatically define the element groups.
SIZE identifies the length of the edge of a
square wherein, all elements within this square are grouped
together. Note: The elements mentioned in EG# in
Format 2 are excluded from the automatic grouping. No default (Real > 0.0) |
|
EG# | Element group numbers
which are excluded from automatic grouping in Format 2. Element
groups are created through element sets (Format 2). 6 Default = blank (Format 2) (Integer > 0) |
|
TAPE | The TAPE flag to indicate that tape laying based free-sizing definitions are active and corresponding parameters are to follow. 12 13 14 | |
LTAPE | Minimum Tape length. No default (Real > 0.0) |
|
WTAPE | Tape width. No default (Real > 0.0) |
|
OFFSET | Allows selecting the
required option to offset contiguous patches.
|
|
MATINIT | Continuation line to define the DSIZE-dependent initial material fraction. | |
VALUE | Default = 0.9 for
optimization with mass as the objective, Default is reset to the
constraint value for runs with constrained mass. If mass is not the
objective function and is not constrained, then the default is
0.6.
This continuation line takes precedence over DOPTPRM,MATINIT for this design variable. |
|
DRAW | Indicates thickness gradient constraints are applied and the corresponding control parameters are to follow. | |
DTYP | Defines the draft angle
type.
|
|
DAID/XDA, YDA, ZDA | Thickness gradient anchor
point. These fields define the anchor point for thickness gradient
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 are in the basic coordinate
system. Default = origin (Real in all fields, or Integer in first field) |
|
DFID/XDF, YDF, ZDF | Direction of vector for
thickness gradient 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
are in the basic coordinate system. No default (Real in all fields, or Integer in first field) |
|
ANGLE | Draft angle (in degrees)
for thickness gradient definition. Default = 1.0 (Real) |
Comments
- There are currently five pattern
grouping options for free-size optimization:
- 1-plane symmetry (TYP = 1)
- This type of pattern grouping requires that the anchor point and the first point be defined. A vector from the anchor point to the first point is normal to the plane of symmetry.
- 2-plane symmetry (TYP = 2)
- This type of pattern grouping requires that the anchor point, first point, and second point be defined. A vector from the anchor point to the first point is normal to the first plane of symmetry. The second point is projected normally onto the first plane of symmetry. A vector from the anchor point to this projected point is normal to the second plane of symmetry.
- 3-plane symmetry (TYP = 3)
- This type of pattern grouping requires that the anchor point, first point, and second point be defined. A vector from the anchor point to the first point is normal to the first plane of symmetry. The second point is projected normally onto the first plane of symmetry. A vector from the anchor point to this projected point is normal to the second plane of symmetry. The third plane of symmetry is orthogonal to both the first and second planes of symmetry, passing through the anchor point.
- Uniform pattern grouping (TYP = 9)
- This type of pattern grouping requires only the TYP field to be set equal to 9. All elements included in this DSIZE entry are automatically considered for uniform pattern grouping. All elements on this DSIZE entry are set equal to the same thickness.
- Cyclic (TYP = 10)
- This type of pattern grouping requires that the anchor point, first point, and number of cyclical repetitions be defined. A vector from the anchor point to the first point defines the axis of symmetry.
- Cyclic with symmetry (TYP = 11)
- This type of pattern grouping requires that the anchor point, first point, second point, and number of cyclical repetitions be defined. A vector from the anchor point to the first point defines the axis of symmetry. The anchor point, first point, and second point all lay on a plane of symmetry. A plane of symmetry lies at the center of each cyclical repetition.
- Linear Pattern Grouping (TYP = 20)
- Linear pattern grouping requires that the anchor point and first point be defined. A vector from the anchor point to the first point defines the direction in which the thickness is set to be constant. Linear pattern grouping is typically designed to handle models with minimal or no curvature in the specified vector direction (which is typically orthogonal to the rolling direction in rolling applications). For models with low curvature in the vector direction, appropriate projections to the surface are used to determine the direction on the surface. For models with high curvature in the vector direction, depending on the direction of the specified vector, the direction may become orthogonal to the surface whereby the pattern grouping direction cannot be determined. In such cases, Planar Pattern Grouping (TYP = 21) is recommended.
- Planar Pattern Grouping (TYP = 21)
- Planar pattern grouping requires that the anchor point and first point be defined. A vector from the anchor point to the first point is defined and thickness of the model in the various orthogonal planes to this vector is set to be constant. Planar pattern grouping is designed to handle models with high curvature in the orthogonal planes of the defined vector, and with minimal or no curvature in the direction of the defined vector. The vector defined in planar pattern grouping should typically lie in the rolling direction in rolling applications. This feature can handle large curvature in the slicing plane orthogonal to the defined vector. Planar pattern grouping cannot be used if large curvature exists in the rolling direction.
Note: Multiple continuation lines defining pattern grouping is allowed. However, this is currently only supported for TYP=20 or TYP=21 in conjunction with TYP=1, TYP=2, or TYP=3.For a more detailed description, refer to Pattern Grouping for Free-Size (Parameter) Optimization contained within the User Guide section Free-size Optimization Manufacturability.
- Pattern repetition allows similar
regions of the design domain to be linked together so as to produce similar
topological layouts. This is facilitated through the definition of "Main" and
"Secondary" regions. A DSIZE card may only contain one
MAIN or SECOND flag. For both "Main" and
"Secondary" regions, a pattern repetition coordinate system is required and is
described following the COORD flag. In order to facilitate
reflection, the coordinate system may be a left-handed or right-handed Cartesian
system. The coordinate system may be defined in one of two ways, listed here in
order of precedence:
- Four points are defined and these are utilized as follows to define the
coordinate system (this is the only way to define a left-handed system):
- A vector from the anchor point to the first point defines the x-axis.
- The second point lies on the x-y plane, indicating the positive sense of the y-axis.
- The third point indicates the positive sense of the z-axis.
- A rectangular coordinate system and an anchor point are defined. If only an anchor point is defined, it is assumed that the basic coordinate system is to be used.
Multiple "Secondary" may reference the same "Main."
Scale factors may be defined for "Secondary" regions, allowing the "Main" layout to be adjusted.
For a more detailed description, refer to Pattern Repetition for Free-Size (Parameter) Optimization contained within the User Guide section Free-size Optimization Manufacturability.
- Four points are defined and these are utilized as follows to define the
coordinate system (this is the only way to define a left-handed system):
- It is recommended that a MINDIM value be chosen which allows for the formation of members that are at least three elements thick. When pattern grouping constraints are active, a MINDIM value of three times the average element edge length is enforced, and user-defined values (which are smaller than this value) will be replaced by this value.
- The von Mises stress constraints may be
defined for topology and free-size optimization through the
STRESS optional continuation line on the
DTPL or the DSIZE card. There are a
number of restrictions with this constraint:
- The definition of stress constraints is limited to a single von Mises permissible stress. The phenomenon of singular topology is pronounced when different materials with different permissible stresses exist in a structure. Singular topology refers to the problem associated with the conditional nature of stress constraints that is the stress constraint of an element disappears when the element vanishes. This creates another problem in that a huge number of reduced problems exist with solutions that cannot usually be found by a gradient-based optimizer in the full design space.
- Stress constraints for a partial domain of the structure are not allowed because they often create an ill-posed optimization problem since elimination of the partial domain would remove all stress constraints. Consequently, the stress constraint applies to the entire model when active, including both design and non-design regions, and stress constraint settings must be identical for all DSIZE and DTPL cards.
- The capability has built-in intelligence to filter out artificial stress concentrations around point loads and point boundary conditions. Stress concentrations due to boundary geometry are also filtered to some extent as they can be improved more effectively with local shape optimization.
- Due to the large number of elements with active stress constraints, no element stress report is given in the table of retained constraints in the .out file. The iterative history of the stress state of the model can be viewed in HyperView or HyperMesh.
- Stress constraints do not apply to 1D elements.
- Stress constraints may not be used when enforced displacements are
present in the model.Note: The functionality of the STRESS continuation line to define topology and free-size stress constraints consists of many limitations. It is recommended to use DRESP1-based Stress Responses instead. Actual Stress Responses for Topology and Free-Size (Parameter) Optimization are available through corresponding Stress response RTYPE's on the DRESP1 Bulk Data Entry. The Stress-NORM aggregation is internally used to calculate the Stress Responses for groups of elements in the model.
- The following manufacturing constraints
are available for composite free-sizing optimization:
- Lower and upper bounds on the total thickness of the laminate (LAMTHK).
- Lower and upper bounds on the thickness of a given orientation (PLYTHK).
- Lower and upper bounds on the thickness percentage of a given orientation (PLYPCT).
- Linking between the thicknesses of two given orientations (BALANCE).
- Constant (non-designable) thickness of a given orientation (CONST).
- LAMTHK, PLYTHK, PLYPCT, and PLYMAN can be applied locally to sets of elements. There can be elements that do not belong to any set.
For a more detailed description and an example, refer to Optimization of Composite Structures in the User Guide.
- Elements within each group will have uniform ply thicknesses.
- The core is designable by default. It can be made non-designable through the CONST manufacturing constraint. To facilitate this, the keyword CORE can be used instead of a ply ID when BYPLY is activated.
- The core is excluded from the LAMTHK, PLYTHK, PLYPCT and PLYMAN manufacturing constraints by default.
- Legacy data field PTMAN (for manufacturable ply thickness) defined on the PLYTHK and PLYPCT entries is supported. However, it is now recommended to define the manufacturable ply thickness in the PMMAN field through the PLYMAN continuation line as this offers more control.
- The options for selecting the type of drop-off constraints for PDTYP are defined for a set of plies.Assuming that the plies are stacked as shown above, you have the following definitions:When OUTPUT,FSTOSZ is used to generate a Sizing input deck, the Ply drop-off manufacturing constraints are converted into equivalent TOTDRP constraints. Check that the estimated TOTDRP values on the DCOMP entry(s) are meaningful, or adjust the values manually, if necessary.
- The optional PDDEF
definition is used to fine-tune the drop-off constraint. Currently, only the
DIRECT option is available for the PDDEF
field.
- PDDEF
- DIRECT This option allows you to fine-tune the drop-off constraint by requesting directional drop-off. The direction of drop-off can be specified by defining a directional vector with respect to the basic coordinate system. The directional vector is defined using the PDX, PDY and PDZ values.
- PDX, PDY, PDZ
- PDX, PDY and PDZ are real numbers.
- Other manufacturing constraints (except BALANCE) can be used along with tape laying.
- If there are multiple plies of the same orientation, the corresponding tapes are automatically offset with respect to one another. This increases the design freedom by allowing OptiStruct to choose the optimum layout for a particular configuration.
- Symmetry is available only at the laminate level for tape laying. Opposite orientations (for example, 45 degrees and -45 degrees) are reflections of each other, instead of being reflected across the plane of symmetry. 0 and 90 degree plies are still reflected across the plane of symmetry.
- Discrete design variables are
internally created based on the thickness step defined via
PMDIS. The thickness step indicates that the design
variables are created as integer multiples of the PMDIS
value. For example, if PMDIS is 0.2, then the design
variables can be 0.2, 0.4, 0.6 and so on. Note: PMDIS and PMMAN can be different. PMDIS is inactive by default and PMMAN=PMDIS by default if PMMAN is not specified.
- When
PTYPE=SET on DSIZE
entry, then:
- The referenced element set can contain elements referring only to PSHELL property.
- If T0 is defined on the DSIZE
entry and/or the PSHELL entry, they must be
consistent. That is,
- T0 on all the DSIZE
entries using elements from the same PSHELL
should match.
For example, DSIZE#1 with T0=0.0 and DSIZE#2 with T0=1.0 and both referring to elements from the same PSHELL is not allowed.
- If T0 on a PSHELL is defined, then its value should match with T0 defined on all DSIZE entries with PTYPE=SET that reference elements from this PSHELL.
- T0 on all the DSIZE
entries using elements from the same PSHELL
should match.
- Multi-material, level set and lattice optimization are not supported
- This card is represented as an optimization design variables in HyperMesh.