2.9. Define Design Constraints

Like the options of the Manufacturing Constraint capability, the options of the Design Constraint capability, as listed below, enable you to impose specific design requirements.

  • Cyclic Repetition: This option enables you to control how the sectors are repeated, at the required times, along the specified axis and yields a design that is symmetric with respect to an axis of rotation.

  • Symmetry: This option enables you to enforce a design that is symmetric with respect to a user-defined plane.

  • Uniform: This option enforces a design that has a constant Topology Density on all planes parallel to a user-defined plane.

  • Pattern Repetition: This option enforces a design that has a repetitive pattern. The pattern is repeated along the specified axial plane with a user-defined offset value.

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Supported Optimization Methods

The Design Constraint options are supported for the following methods only:

Density BasedLattice OptimizationLevel Set BasedMixable DensityShape OptimizationTopography Optimization
Cyclic Repetition
Symmetry
Uniform
Pattern Repetition
Pattern Repetition
Cyclic Repetition
Symmetry
Pattern Repetition
Cyclic Repetition
Symmetry
Pattern Repetition
Cyclic Repetition
Symmetry
Not Applicable

Requirements and Restrictions

Note the following requirements and restrictions for design constraint types. The restrictions only apply when one of the types is scoped to an Optimization Region or if it has an overlapping region.

  • Only one Uniform constraint can be specified per analysis.

  • Only one Cyclic Repetition constraint can be specified per analysis.

  • If you specify two Symmetry constraints, the symmetry planes must be perpendicular to one another.

  • If you specify a Symmetry and a Cyclic Repetition, the given symmetry plane must be perpendicular to the axis of rotation.

  • If you specify a Symmetry and a Uniform, the symmetry plane must be parallel to the plane of the uniform constraint.

  • If you specify two Pattern Repetition constraints, the axis planes must be perpendicular to one another.

  • The combination of the following subtypes is not supported:

    • Cyclic Repetition and Uniform

    • Extrusion and Uniform

    • Pull Out Direction and Uniform

  • Note the following restrictions when you specify a Manufacturing Constraint and a Design Constraint with the Subtype combinations:

    • For Symmetry and Extrusion, the extrusion direction must be in the symmetry plane.

    • For Symmetry and Pull Out Direction, the pull out direction must be in the symmetry plane.

    • For Cyclic Repetition and Extrusion, the axis of rotation of cyclic constraint must be in the same as the extrusion direction.

    • For Cyclic Repetition and Pull Out Direction, the pull out direction and the cyclic axis of rotation must be the same.

  • If you specify Pattern Repetition, in combination with:

    • Symmetry, the pattern direction must be in the symmetry plane.

    • Cyclic Repetition, the pattern direction must be the same as the rotation axis.

    • Extrusion, the pattern direction must be perpendicular to the extrusion direction.

    • Pull Out Direction, the pull-out direction must be perpendicular to the pattern direction.

    • Uniform, the plane of the uniform constraint must be perpendicular to the pattern direction.

Application

The analysis can include only one Design Constraint object.

  1. To add the object, either look on the Environment Context tab and select Design Constraint > [Subtype] or right-click the Environment object or within the Geometry window and select Insert > [Subtype].

  2. Based on the selected Subtype, specify properties as required.

Details Properties

The Details pane for this object includes the following properties.

CategoryProperties/Options/Description

Scope

Scoping Method: Based upon the type of Design Constraint you have inserted into the tree, one or more of the following options is available for this property:

  • Geometry Selection: This option indicates that the design region is applied to a geometry or geometries, which are chosen using the graphical selection tools. When you specify Geometry Selection for the Scoping Method, the Geometry property displays.

    In this case, use selection filters on the Graphics Toolbar to pick your geometric entities (body and element selection only), and then click Apply. Once complete, the property displays the type of geometry (Body, Element, etc.) and the number of selected geometric entities (for example: 1 Body, 12 Elements).

  • Named Selection: This option indicates that the design region is applied to a Named Selection. When you specify Named Selection for the Scoping Method, the Named Selection property displays. This property provides a drop-down list of available user-defined Named Selections (only body-based and element-based Named Selections are supported).

  • Optimization Region: This option indicates that the design region applied to the specified Optimization Region. When you select Optimization Region for the Scoping Method, the Optimization Region Selection property displays.

  • All Optimization Regions: When you have multiple Optimization Regions, this option indicates that the constraint is applied to all defined Optimization Regions.

Definition

Type: This is a read-only property that indicates the object as a Design Constraint.

Subtype: This property is a read-only field and it displays the type of Design Constraint you selected from the Design Constraint drop-down menu.

  • Cyclic Repetition

  • Symmetry

  • Uniform

  • Pattern Repetition

Location and Orientation

When a subtype is selected, their associated properties display in the Location and Orientation category of the Details:

Cyclic Repetition

When this subtype is selected, the following associated properties display:

  • Number of Sectors: This property specifies the appropriate number of sectors.

  • Coordinate System: Specify an appropriate Cartesian or Cylindrical coordinate system for the cyclic model.

  • Axis: Specify the appropriate axis. Options include: X-Axis, Y-Axis, Z-Axis. Only the Z-Axis option is supported for a Cylindrical coordinate system.

Symmetry

When this subtype is selected, the following associated properties display:

  • Coordinate System: Specify the appropriate Cartesian coordinate system for the symmetry model.

  • Axis: Specify the plane for the symmetry model. Options include: YZ Plane, XZ Plane, and XY Plane.

Uniform

When this subtype is selected, the following associated properties display:

  • Coordinate System: Specify the appropriate Cartesian coordinate system for the uniform constraint.

  • Axis: Specify the appropriate plane. Options include: YZ Plane, XZ Plane, and XY Plane.

Pattern Repetition

When this subtype is selected, the following associated properties display:

  • Coordinate System: Specify the appropriate Cartesian coordinate system for the repetitive pattern.

  • Axis: Specify the appropriate axis. Options include: X-Axis, Y-Axis, and Z-Axis.

  • Offset: Specify the appropriate offset after which the pattern is repeated.