Week 5 Challenge : Surface wrap on Automotive Assembly

https://drive.google.com/file/d/1V3TW_CtgJjaCwnxnVMYPezZsGJGlfxga/view?usp=share_link

Objective:

The goal is to clean the surface geometry to avoid errors and create a surface wrap that accurately captures the input domain geometry (a powertrain control) with high-quality cells so as to make subsequent calculations intractable. The element size for various parts is as shown below:

• Target length of Wrap: 3 mm

Mesh generation:

Mesh generation is the practice of creating a mesh, a subdivision of a continuous geometric space into discrete geometric and topological cells. Often these cells form a simplicial complex. Usually, the cells partition the geometric input domain. Mesh cells are used as discrete local approximations of the larger domain.

Purpose of meshing:

Meshes are used for rendering to a computer screen and for physical simulation such as finite element analysis or computational fluid dynamics.

Finite element calculations cannot be done directly on solid parts. We know to perform those calculations only on points created by the mesh generation process. Thus generating mesh is a must and most important step for any CFD or FEA calculations to be performed.

Surface wrap:

The surface wrapper can be used to provide a closed, manifold, non-intersecting surface when starting from poor quality CAD data. It is typically used when the imported surface includes problems such as:

• multiple, intersecting parts;
• missing data in the form of holes and gaps;
• surface mismatches;
• double and internal surfaces; and
• overly-complex geometry with too much detail;

The surface wrapper can achieve many different aims simultaneously when applied to such data. These include:

• Provide a closed, manifold, triangulated surface definition;
• close holes, gaps, and mismatches;
• "skin" double surfaces and remove internal features;
• simplify the surface geometry by removing unwanted detail;
• include baffle thickness inflation for desired internal features; and
• include refinements based on curvature, proximity and/or individual surfaces

The resulting surface quality from the surface wrapper is not optimal so it is usually used in conjunction with the surface remesher to provide a high-quality starting surface for the volume meshers.

Steps involved in geometry clean-up by ANSA:

1. The solid part made using any cad modeling software is imported into ANSA. The Procedure is File>Open and select the required solid part.
2. The solid part is initially imported as a wireframe model in ANSA and it is changed into a solid model by clicking on the surface icon as shown below.
3. We have 6 unchecked faces and we used untrim option to clear the unchecked faces.
4. before performing the surface wrap we delete the unwanted reference models which were used such as the rings, sphere, balls as these are not essential.
5. You can highlight any of the problematic areas by left-clicking on it, or isolate it on the screen by right-clicking on it and selecting “Show only”. Depending on the type of problem ANSA also offers the option to automatically fix it.
6. Before performing surface wrap we close all the open surfaces in the model because when we apply the wrap on the model before closing the open surfaces it will create skewness on the model so we do first close all the open surfaces.

7.De-activate “Shadow” mode and the visibility flag button for “Double” CONS. You will now isolate a region of your part to work on. Activate the “Or” function located in the Focus Toolbar. Make a box selection of the area shown on the left using the left mouse button. The “Or” function leaves visible only the selected Faces. (If you accidentally select wrong Faces, press the All function of the same Group to bring all the entities back to visible).

8. Activate the “Lock” flag button in the Focus Toolbar to lock the currently visible entities. Now when you press the “All” button, only the selected and locked entities will become visible.
9. To view the complete Faces that you have left visible, activate again the “Double” CONS visibility flag. Activate also the “Cross Hatches” visibility flag. This allows the visualization of two green dashed lines along the center isoperimetric of the Faces. Apart from visualization purposes, the crosshatches are also used for selecting Faces.
10. In order to close the open holes we initially release all the cons and we use the fill hole option to completely close all the open holes. The model after closing all the open holes is shown below.
11. Similarly the other two parts namely gearbox and transmission box is cleaned up and the holes are closed as shown below.

Steps involved in merging different parts and defining models in the model browser in ANSA:

• Next step is to merge the three different parts into a single assembly.
• go to file>merge>and select the different parts. The merged assembly is shown below
• Set Wrap Parameter
• PID Compress 1583 to 90(The empty part is the leftovers of the deleted components. It occupies an unwanted system space and creates confusion. Compress option is used to delete the temporary files.)
• Contents add
• Then click run

Steps involved in creating a single continuous volume in ANSA:

1. The merged model is made up of three different volumes but the idea is to create a part comprising of a single continuous volume.

2.first the intersecting regions are isolated using not and i-not operators as shown below

3. Now the intersecting area is deleted and manipulated by using various tools namely delete, mvsurf, and release nodes options.
4. after removing the intersecting area, The connections are made using paste, fill, and new elements options. After performing these operations the below connection is made.
5. Similarly, the intersecting area between the transmission box and the engine is isolated as shown below.
6. Here a new technique i used to create a volume. New elements are created using the above-said tools and the intersecting PID region is deleted as shown below.
7. Finally, the seamless connection is obtained in the assembly as shown below

Conclusion:

1. Three individual parts are successfully surface wrapped with constant Wrap sizes.
2. The individual models are merged together and a single continuous volume is created.

both files are uploaded

1. Report

2. Model