Goal of this tutorial

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 Jet Engine Bracket the already prepared Design Space was imported.

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

• Create the material Titanium in the Materials editor and assign it to the Design Space. In this case the material behaviour is Isotropic (Primary material model)

• The specific values needed are the Elastic Modulus (Young’s Modulus) 1.16E+5 MPa, Poisson ratio 0.26 and Density 4.48E-6 kg/mm³.

• The Tension Strength is the maximum allowable stress for the material and is set to 1290 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.

Creation of local coordinate systems to apply forces

Because the imported Jet Engine Bracket CAD-file is shifted and rotated to the global coordinate system, local coordinate systems can be used to apply the forces and moments.

By opening the Coordinate Tools a local coordinate systems can be placed on the bottom plane (coordinate system 2).

To apply the forces the Loads & Boundary Condition Tool is needed. Select the two upper faces at the same time. By disabling the Thunderbolt (tool execution mode selector) in the top left corner of the tool settings, both surfaces can be selected simultaneously and a Remote Force between them can be applied. In the Orientation field an external (local) coordinate system can be selected (coordinate system 2).

Two loads and one Moment are created with the given values in the table. They are all referring to the Local Coordinate System 2.

For Force - Moment 4 a second local coordinate system is needed. This one is rotated by 42 degrees for the z-axis (beta-angle). This can be done by adding 42° (180.5°) to the beta-angle after choosing the same plane as coordinate system 2.

Force - Moment 4 is also applied on the surfaces of both Non-Design Spaces in z-direction. Now the orientation is referred to the coordinate system 3.

Four constraints are created:

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 surfaces are selected.

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. There are two options to create these interfaces. The interfaces can be created either manually or the Boundary Condition surfaces will be highlighted automatically and can be selected/deselected. In this Tutorial the automated option is used.

• Two Interfaces are created for the load application surfaces. Therefore, an Non-Design Space Thickness of 2 mm and a Machining Allowance of 1 mm is entered. Because not only the inner faces touching the screw but also the front and back face are supposed to contain material and have sharp, functional faces, an Offset Distance of 3 mm is entered. Now the faces for the interfaces can be detected automatically with the “Select Faces from Loads and Boundary Conditions” button. Since this function will select all faces from loads and boundary conditions, the desired options must be selected. In this case the interfaces for the load application surfaces will be created therefore the constraints must be deselected.

• Four Interfaces are created on the faces of the fixations. Therefore, an Non-Design Space Thickness of 3 mm and a Machining Allowance of 1mm is entered. Because not only the inner faces touching the screw but also the front and back face are supposed to contain material and have sharp, functional faces, an Offset Distance of 3 mm is entered. Now the faces for the interfaces can be detected automatically with the “Select Faces from Loads and Boundary Conditions” button. Since this function will select all faces from loads and boundary conditions, the desired options must be selected. In this case the interfaces for the constraints surfaces will be created therefore the Loads must be deselected.

Step 5: Definition of Events (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.

• For each Force - Moment a separate Event is created including the Constraint:

Step 6: Definition of optimisation parameters

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

• Manufacturing Method: Generic AM

• Failure Criteria: Von Mises

• Stress Goal: 600 MPa (Safety Factor: 2.15)

• Strut Density: Medium

• Shape Quality: Balanced

• Complexity Setting: 14

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 64 iterations (Shape Quality: Balanced).

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 run.

Step 8: Visualization of Stresses & Displacements

• Inside the Post Processing the von Mises stress and the displacements are visible for all iterations and for every Event. The Scale can be influenced individually

You can go back to the model setup by clicking the Exit button in the right bottom corner.

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

You might also be interested in these tutorials:

• Generative Design - Bookshelf

• NURBS Retransition Full Workflow - Jet Engine Bracket

• Anisotropic Material Behaviour & the influence of different Failure Criteria - Hook

• Generative Design - Command Line Optimisation

• Support Reduction - Gripper