2.3. Specify Analysis Settings

This topic examines the application defaults for Analysis Settings properties based on the optimization method. For a general overview of the use of analysis settings, see the Establish Analysis Settings section.

Analysis Settings per Method

Density Based Optimization

For the Topology Optimization - Density Based method, you can modify the properties as described below.

Reload Volume Analysis

The Reload Volume Analysis category of the Analysis Settings is only available when performing a Structural Optimization analysis and it only displays following the solution process. This category includes the Reload Volume Fraction property. The options for this property include Off and Manual. When you set the property to Manual, the Current Reload Point property also displays and provides the following options:

Initial: Using this setting, your next solution begins from Iteration 0 (a new solution).
Iteration Number ##: This setting is based on the last Iteration completed for the previous solution. Using this setting, your next solution begins by reloading the volume fractions at the specified iteration number.

Note: When you pick a reload point that is different from the Initial reload point, you may receive an optimized shape that is different than the optimized shape obtained when you perform the optimization from the beginning of the analysis.

Important: If you modify any of the following, the Reload Volume Analysis category disappears from the Analysis Settings:

Manufacturing Constraints (You can use the Pull Out Direction Manufacturing Constraint for Reload Volume Analysis if you set the Region of Manufacturing Constraint property to Exclude Exclusion)
Optimization Region
Region of Manufacturing Constraint property
Region of Min Member property
Size property
Any associated upstream system

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Minimum Normalized Density: This property requires a value greater than 0 and less than 1. The Structural Optimization analysis uses this value to extract the permissible range of retained threshold values. The default value is 0.001.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. This value must be less than or equal to 2. The default value is 0.1%.
Note: Specifying a lower Convergence Accuracy, for example 0.05%, is recommended if your optimization objective is to minimize Mass/Volume with Global/Local von-Mises stress constraint.
Initial Volume Fraction: This property requires a value greater than 0 and less than or equal to 1. The optimization analysis uses this value as an initial estimate for the volume fraction. All optimized elements begin with this value. By default, the application uses your specified Objectives and Constraints to determine the initial estimate. A value of 1 indicates full material, whereas all other values indicate a fraction of the original material.
Penalty Factor (Stiffness): During the solution process, this property applies a penalty factor to the structural stiffness matrix in order to prevent the stiffness matrix from scaling linearly with the pseudo density. Therefore, the stiffness at each iteration, as needed, is modified using the expression: . The default value is 3.
Region of Manufacturing Constraint: The options for this property are Include Exclusions (default) and Exclude Exclusions. When you specify Include Exclusions, the application also incorporates the Exclusion Region to satisfy the Pull Out Direction, Extrusion, Cyclic Repetition, and Symmetry manufacturing constraints.
Region of Min Member Size: The options for this property are Include Exclusions and Exclude Exclusions (default). When you specify Include Exclusions, the application also incorporates the Exclusion Region to meet the minimum member size specified through the Member Size manufacturing constraint.
Region of AM Overhang Constraint: If your analysis includes the specifications of an AM Overhang Constraint, this property enables you to include or exclude the object on the Exclusion Region of the model. The options for this property are Include Exclusions and Exclude Exclusions (default). When you specify Include Exclusions, the application applies the AM Overhang Constraint to the Exclusion Region.
Filter (Density Based method only): This property specifies the method used to calculate the pseudo density of each element. Options include:
- Linear: A faster processing option than Non-Linear, this option may prefer placing material on the boundary of your design domain as well as cause the Minimum value of the Member Size property to infringe upon the boundary of the design domain.
- Non-Linear (Program Controlled default): This option uses more advanced algorithms to calculate the pseudo densities that resolve the drawbacks of linear filtering.
Note: Ansys recommends that you exclude all areas where loads are applied.

Output Controls

The properties of the Output Controls category include:

Export Design Properties. This property is only available for a Structural Optimization analysis when you have an upstream Static Structural or Modal analysis system. You use the options of this property to specify when the application creates solution data. You can then create Deformation, Stress, Strain, etc., results in your Structural Optimization analysis that correspond to your upstream analysis. These results enable you to examine the mechanical behavior of your optimal design (corresponding to the last accepted iteration) as well as the mechanical behavior of intermediate designs. Property options include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Export Design Properties File Format: This property displays when you specify the Export Design Properties property. Options include HDF5 File (default) and VTK File (requires external reader).

Important: Strain-based results are not supported for the Topology Optimization - Density Based method.

Note: These structural results are displayed on a triangle-based surface-mesh.

Store Results At: Based on the analysis type, specify this time to be All Time Points or All Iterations (default setting), Last Time Point or Last Iteration, Equally Spaced Points or Specified Recurrence Rate.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Solver Controls Category

The Solver Type property is the only property for this category. The property's options include:

Program Controlled (default): The application selects the Sequential Convex Programming solver as the default option.
Sequential Convex Programming: The Sequential Convex Programming method is an extension of the method of moving asymptotes (MMA). The Sequential Convex Programming method requires the derivatives of all functions present in the Structural Optimization analysis.
See the Optimization Solver Methods section for additional technical detail about this solver type.
Optimality Criteria: The Optimality Criteria method can be used to solve Structural Optimization problems with a simple compliance objective that uses a volume or mass constraint.
Note: The following support limitations apply to the Optimality Criteria method:
- Only supports the Compliance (Structural) setting for the Response Type column of the Objective object worksheet.
- Only Volume and Mass constraints are supported.
- The Manufacturing Constraint is supported where only the Minimum property for the Member Size constraint subtype can be specified.
See the Optimization Solver Methods section for additional technical details about this solver type.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.

Level Set Based Optimization

For the Topology Optimization - Level Set Based method, you can modify the properties as described below.

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 0.1%.

Output Controls

The properties of the Output Controls category include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Note: These structural results are displayed on a triangle-based surface-mesh.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.

Lattice Optimization

For the Lattice Optimization method, you can modify the properties as described below.

Reload Volume Analysis

Initial: Using this setting, your next solution begins from Iteration 0 (a new solution).
Iteration Number ##: This setting is based on the last Iteration completed for the previous solution. Using this setting, your next solution begins by reloading the volume fractions at the specified iteration number.

Important: If you modify any of the following, the Reload Volume Analysis category disappears from the Analysis Settings:

Manufacturing Constraints (You can use the Pull Out Direction Manufacturing Constraint for Reload Volume Analysis if you set the Region of Manufacturing Constraint property to Exclude Exclusion)
Optimization Region
Region of Manufacturing Constraint property
Region of Min Member property
Size property
Any associated upstream system

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Minimum Normalized Density: This property requires a value greater than 0 and less than 1. The Structural Optimization analysis uses this value to extract the permissible range of retained threshold values. The default value is 0.001.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. This value must be less than or equal to 2. The default value is 0.1%.
Note: Specifying a lower Convergence Accuracy, for example 0.05%, is recommended if your optimization objective is to minimize Mass/Volume with Global/Local von-Mises stress constraint.
Initial Volume Fraction: This property requires a value greater than 0 and less than or equal to 1. The optimization analysis uses this value as an initial estimate for the volume fraction. All optimized elements begin with this value. By default, the application uses your specified Objectives and Constraints to determine the initial estimate. A value of 1 indicates full material, whereas all other values indicate a fraction of the original material.
Region of Manufacturing Constraint: The options for this property are Include Exclusions (default) and Exclude Exclusions. When you specify Include Exclusions, the application also incorporates the Exclusion Region to satisfy the Pull Out Direction, Extrusion, Cyclic Repetition, and Symmetry manufacturing constraints.

Output Controls

The properties of the Output Controls category include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Note: These structural results are displayed on a triangle-based surface-mesh.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Solver Controls Category

The Solver Type property is the only property for this category. The property options include:

Program Controlled (default): The application selects the Sequential Convex Programming solver as the default option.
Sequential Convex Programming: The Sequential Convex Programming method is an extension of the method of moving asymptotes (MMA). The Sequential Convex Programming method requires the derivatives of all functions present in the Structural Optimization analysis.
See the Optimization Solver Methods section for additional technical detail about this solver type.
Optimality Criteria: The Optimality Criteria method can be used to solve Structural Optimization problems with a simple compliance objective that uses a volume or mass constraint.
Note: The following support limitations apply to the Optimality Criteria method:
- Only supports the Compliance (Structural) setting for the Response Type column of the Objective object worksheet.
- Only Volume and Mass constraints are supported.
See the Optimization Solver Methods section for additional technical details about this solver type.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.

Shape Optimization

For the Shape Optimization method, you can modify the properties as described below.

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 0.1%.

Output Controls

The properties of the Output Controls category include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Note: These structural results are displayed on a triangle-based surface-mesh.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.

Mixable Density Based Optimization

For the Topology Optimization - Mixable Density method, you can modify the properties as described below.

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 0.1%.

Output Controls

The properties of the Output Controls category include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Note: These structural results are displayed on a triangle-based surface-mesh.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.

Topography Optimization

For the Topography Optimization method, you can modify the properties as described below.

Definition Category

The Definition category of the Analysis Settings is only available when performing a Structural Optimization analysis. The properties of the Definition category include:

Maximum Number of Iterations: This property specifies the maximum number of iterations performed for the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 500.
Convergence Accuracy: This property specifies the convergence criteria of the Structural Optimization analysis. The solution process continues until the application achieves convergence accuracy or reaches the maximum number of iterations. The default value is 0.1%.

Output Controls

The properties of the Output Controls category include:

No (default): No solution data is generated.
On Final Design: Solution data is created at the end of the optimization process. This corresponds to the last accepted iteration (optimal design).
All Accepted Iterations: Solution data is generated after each accepted iteration of the optimization process. That is, the solution data includes all accepted iterations.
Last Accepted Iteration: Solution data is generated during the optimization process that corresponds to the last accepted iteration. That is, the single data is updated during the optimization in accordance with the latest accepted design.

Note: These structural results are displayed on a triangle-based surface-mesh.

Value. Displayed only if Store Results At is set to Equally Spaced Points or Specified Recurrence Rate.

See Output Controls section for additional information about the properties of this category.

Analysis Data Management Category

See the Analysis Data Management Category section of the Help for additional information about the properties of this category.