University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 1

The basics of NX – CAD 1) Creation of a new file: Go to File/New/Model and create a model part named Cantilever.

Create a folder for your project and save every file on it.

2) Start a new Sketch and draw a rectangle of 800x300

Select the plan XY to start the sketch. Position the rectangle with respect to the origin in order to have a good local reference.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 2

3) Finish the sketch and

extrude it by 600

Then save and close the part model

The basics of NX – FEM 4) Start a new FEM named as Cantilever_fem.

- As a master part, associate the file Cantilever.prt

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 3

5) In order to mesh with hexahedral elements, prepare the 2D-map.

- Select “2D Mapped”, pick two opposite surfaces and set the element size to 25.

6) Extrude the mesh to obtain a discretization with hexahedral elements.

- Select “3D Swept Mesh” and pick the two mapped surfaces. Set the element size to 25 mm and press OK.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 4

7) Apply the physical properties to the elements

- Apply the physical properties to the mesh.

- Delete the 2D meshes that you created

8) Create a new sim file and name it as Cantilever_sim

- Select the file Cantilever_FEM.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 5

9) Clamp the face and apply the loads

- Select the constraint type: Fixed constraint, and pick one face of the cantilever beam. - The forces are applied on the nodes. To do that is useful to select “Nodes” in the filter selection window.

- Select Force as a Load Type and apply a force of 4000 N pointing in –Z direction (down). - Apply a second force of 1000 N pointing in Y-direction (horizontal).

10) Define the two load cases

Once is cloned, change their names as proposed in the right picture and remove the Force(1) and Force(2) where appropriate.

- The Solution 1 in the Navigator looks like this:

- To add a new load case, right click on “Subcase – Static Load 1” and select clone.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 6

11) Check the model

- Before launching the simulation it is important to check the consistency of the model. Solve your model by clicking on “Solve”. - Once it is finished, double click on results then expand the navigator to go through the results.

12) Perform the optimization

- Chick on the Topol Icon to open the software. - Select the parameters depicted in the pictures and then click on Start TOPOL. - You can check the compliance by clicking on it in the Results Plot window.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 7

The basics of NX – Post Processing

13) Check the optimized structure

- Double click on results and then expand Structural/Topol and double click on Mass Density.

- You can see the purged solution by removing the void elements.

14) Generate the jt file.

- Activate the void elements. - Open Topol Post Processing.

- Select 0.30 as density cutoff. - Click on average smoothing. - Give a name to the JT file and select the destination folder.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 8

15) Smooth the solution

- Once the JT file is generated, open it and go to Application/Modeling

- Go to Reverse Engineering to perform the treatment over the JT file.

- You can increase the smoothness of the structure by going to “Smooth”. - A smooth structure is easier to convert into a solid model. - Go to Convert Facet Body and select the options shown in the figure and then click OK. If the surface is closed and smooth, the previous process should produce a solid model. If it is not the case, the surface will require more post treatment. - The solid part can be manipulated with boolean operations.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 9

TOPOL with passive elements

1) Creating the assembly

- To create passive elements it is necessary to split the model part. - Create another part model. Create a plate of 100x100x25 mm with a hole in the middle of 20 mm diameter, as shown in the picture. This part will be defined as non-optimizable zone. - Different parts will compose the final structure which must be assembled. To do that create a new assembly file and name it cantilever_2. - Assembly the model as it is shown in the picture. To do that it is necessary to add new components, and to apply constraints in the form of “touch” or “align”.

- During the constraint operation, the first part selected it is going to be moved. Hence, it is recommendable to select the big block as a second option, in that way the local reference is kept in the middle of the structure. - Once the assembly is done, save and close.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 10

2) Create the FEM.

- Start a new fem and load the assembled file. - Mesh the main block following the steps 5-7 of the previous tutorial. - Mesh the supports with 3D tetrahedral elements of size 25 mm. - Delete the 2D mesh (right click on the mesh and delete it)

- Go to mesh mating and create a glue non coincident condition. This process will ensure a coincidence of meshes.

- Finally, delete all the 2D meshes.

University of Liège, Aerospace and Mechanical Engineering department

MECA0027 – Project III – Topology Optimization for Industrial Applications / Academic year 2017-2018 11

3) Create the SIM

- Start a new fem file and load the previous fem model. - Define the same load cases than in the previous example, i.e. vertical and horizontal forces acting on the nodes. - Clamp the holes of the square plates. - Define the non-optimizable zones by creating a Region named TOPOLFIX. (Right click on “Regions” and then “new”). - Solve the static problem to check the model. - Run the optimization with the same parameters than the previous example. Then check results.