Lennart

Training:

Relevant data for this tutorial:

Step 1: Start MSC Apex Generative Design

The program starts and you can directly create your optimisation model

Step 2: Model generation

You can either create the geometry directly in MSC Apex Generative Design or import already existing files. You can import for example .xb, .xt, .step, and .sldprt files into the program.

• Import/create the Design Space including the Non-Design Spaces in MSC Apex Generative Design as one solid. For this Gripper the already prepared Design Space was imported.

• Open the Optimization Tools to select the imported Geometry as the Design Space

Material Assignment

• Create the material in the Materials editor and assign it to the Design Space

• The specific values needed are the Young's Modulus (72 000 MPa) and the Poisson ratio (0.34). The density is set to 2.7e-6 kg/mm³.

• The Tension Strength is the maximum allowable stress for the material and is set to 460 MPa.

Step 3: Definition of boundary conditions

Go to the Loads & Boundary Condition Tool to enter the loads and fixations. Displacements, Forces, Moments, Gravity and Pressure Loads can be applied using different selection options.

Three remote loads are created on the shown surface with the given values in the table. After creating the first one, this load can be cloned in the model tree and adjusted according to the direction and value in the table below to Force - Moment 2 and 3.

Moreover, three gravity loads are created.

Two Constraints on the mounting holes inner surfaces are created:

Therefore, the Loads & Boundary Condition Tool is needed.

Under Displacement Constraints a “clamped” constraint can be chosen, which locks translations in all three directions. On the left side of the Tool the relevant geometry choice can be selected. In this case the inner surfaces of the mounting holes are selected to attach the constraint.

Step 4: Interface Creation

Interfaces have to be created for every functional surface - so every surface where a boundary condition is applied to. With this Tool an offset to the inside with the input “Non-Design Space Thickness” and an offset to the outside with the input “Machining Allowance” is created. The Offset Distance is expanding the Interface to the set value to create material on front faces.

All surfaces on which a boundary condition is applied can be selected directly as an interface with the “Select Faces from Loads and Boundary Conditions” button. The Boundary Condition surfaces will be highlighted and can be selected/deselected. With “Apply” the Non-Design Space Thickness, Machining Allowance and if available Offset Distance values will be applied to the selected surfaces.

• In this case an Non-Design Space Thickness of 3 mm and a Machining Allowance of 1 mm is entered.

Note: Sometimes the Interface Offset (usually displayed in red) is not visualized due to a limitation. The correct value will be considered in the optimisation.

Step 5: Definition of load cases

The next steps are defined in the Studies area.

All boundary conditions must be assigned to the specific load cases, which are defined as Events. The number of Events can be changed by adding/deleting Events to the GD Scenario. The assignment of the boundary conditions to the Events can be made in the Loads & Constrains Window. The already created loads and constraints that concern the Design Space are listed in this window and can be activated for each Event individually.

• Event1: Force-Moment 1, Constraint 1, Constraint 2

• Event2: Force-Moment 2, Constraint 1, Constraint 2

• Event3: Force-Moment 3, Constraint 1, Constraint 2

Step 5: Definition of optimisation parameters and Generative Design Settings

The optimisation parameters are selected in the Studies Area as well.

• Select the Manufacturing Method: Generic AM

• Selected the Failure Criterion: von Mises

• Enter the Safety Factor: 5.75 (80 MPa)

• Select the Strut Density: Medium

• Select the Shape Quality: Fine Tune

• Set the Complexity Setting: 8

Step 6: Activating Support Reduction

With the 2022.1 version the Support Reduction is introduced as an experimental feature. It can be activated using the Advanced User Settings.

For the Support Reduction the global Z-direction is always the build direction.

• Exception: If symmetry is activated, the z-direction of the symmetry coordinate system is the build direction.

• If Support Reduction is used in combination with Anisotropic Material Behaviour, the X-direction of the Material Coordinate System should be aligned with the global Z-direction.

Three different modes can be used which are described more detailed here.

For the modes Reactive and Active the Intensity can be influenced as an additional option. The default value for the intensity is 5.

In this case the Passive mode is used which is the lightest level.

You can check the status of the optimisation in the GD Status and get more information on Warning and Error messages. This can be done directly in the Post-Processing as well as in the Studies tab for an optimisation that has already been executed.

Step 7: Starting the optimisation and visualize the results

If all data is correct, the optimisation can be started and tracked in the Post Processing. The Analysis Readiness function checks if all information is provided and the optimisation can start.

All result iterations are displayed as soon as they are available. Furthermore, you are able to stop the optimisation in this selection area. However, a Restart is not directly possible.

The optimisation is finished after 70 iterations (Shape Quality: Fine Tune).

Step 8: Visualization of Failure Criteria, Displacements etc.

• Inside the Post Processing the Stresses, Failure Criteria, the Displacements, the Optimisation Achievement index and the volume/mass are visible for all iterations

• The Scale can be influenced individually

• With the buttons in the bottom bar it is possible to switch between the Nominal-, Print- and Smooth-Geometry. All of them can be exported as an STL-file or transferred directly back to the Pre Processing.

Influence of Support Reduction Strategies

The Support Reduction function creates print-ready geometries with a perfect ratio between support reduction and part performance. It reduces the required amount of support structure for the manufacturing process with nearly the same mechanical performance as without Support Reduction (Base-Design).

In the picture below the left side shows the Base-Design without Support Reduction and the right side the design with Support Reduction (passive strategy). The area where the most support structure is needed is reshaped in such a way that the support strucutre is reduced significantly.

The passive Support Reduction reduces the required support structure about 75% at 3% less mass. As a small trade-off the max. deflection increases by 5%.

The Support Reduction Strategies Reactive and Active with a Support Reduction Intensity value of 5 reduce the required support structure even more - 85% of the initial support structure can be saved.

The whole MSC Apex Generative Design project with all results can be downloaded here:

You might also be interested in these tutorials:

• Generative Design - Jet Engine Bracket

• Restart Optimisation