FEA Report Outline

Owned by Jens Dekker
Last updated: May 15, 2023
6 min read

Welcome to FEA! FEA stands for Finite Element Analysis and is what the team uses to simulate the stresses your parts will experience in use.

The best place to begin is with this tutorial made by Mido a while back SolidWorks FEA 101

This page is meant to give you some more info and help organize your findings.

Some general tips/procedures I want to add in are:

  • Title your page with the day you finished it! → Makes it easier to keep track of revisions

  • You’ll see a page for each week which will house all the FEA reports from that week. When you’ve finished up, I want you to change the status of the part you’re working on and highlight it green or red for pass or fail respectively. But do it for the cell background tho.

  • Make sure your Mesh is fine enough → make sure that each section has at least two nodes

This is a bad mesh since it’s there’s only a single node between the two faces.

This is a better mesh since there’s two nodes between the two faces.

And the more nodes the better! It just takes more time to run the simulation.

  • Make sure the correct faces are selected for loads and fixtures and use split lines to highlight the correct sections.

Start off by making a sketch of where you want split lines.

Exit the sketch and go to split line.

Select “Projection,” the sketch you made, and the face(s) you want to split.

This result in the face being split so you can select certain areas for loads and fixtures.

 

  • Don’t simulate off-the-shelf (OTS) parts → we choose parts that we know will withstand the loading, you won’t need to simulate them, makes everything more complicated

  • Add whatever file you used to your Confluence page (the SolidWorks file with the simulation and an Excel sheet with the mesh convergence data).

Table of Contents

The sections with an asterisk* are useful to know but should not be in the report.

And the section with a tilda~ need to be included in your report if you have multiple parts in a single assembly you need to simulate.

Loading

In the tutorial Mido made he would’ve gone over how to add a force to a part. Basically do that.

Just add the screenshots of what faces you selected.

Fixtures

Mido’s tutorial would’ve also gone over how to add fixtures. One tip I’ll add is that connections

Like in Loading, just add screenshots so I know what you selected.

Interactions~

There’s going to be some parts there will be welded together and act as a single piece. This means you’ll need to run the simulation in an assembly and set the interactions between all the parts. I’m pretty sure the default is that all parts would be “Bonded” which means that every part in contact is glued/welded together. There might be some cases where you use dummy parts to put forces on parts, but that’s something we can talk about if your simulations aren’t making a lot of sense.

Anyways, here’s a link that explains the different interaction you can set up between parts in SolidWorks. The main ones you’ll be using are “Bonded” and “Contact.” We don’t ever use “Free.”

Types of Interactions - 2021 - SOLIDWORKS Help

Bolted Joints*

Most parts in our systems will be bolted together in one form or another, so understanding how bolted interactions function is pretty important.

The short of it is that the we rely on the friction between the bolt and the part to transfer forces between parts. The holes that bolts sit in are larger than the diameter of the bolt (usually a called a clearance fit). This means that the face of the bolt or nut are going to be in contact with the part before the circumference of the bolt. Enjoy this MS Paint art I made in a minute that tried to explain this better

Here’s where preload enters the picture. Preload compresses the parts that are bolted together, which means the bolt is in tension (remember that forces internal to a system net zero). Think of it as tightening a nut too much. This preload results in normal forces between the part and bolt. Therefore frictional forces are in effect and are what transfers forces acting radial to the bolt between the parts bolted together.

 

Mesh Refinement~

In some cases it doesn’t make sense to decrease the size of the mesh of the entire part, since that would increase the running time of the simulation. But we can decrease the size of the mesh in specific areas, specifically where we expect higher stresses. That way we see the most realistic results in the areas we’re most concerned about, while keeping the simulation a reasonable running time.

Make smaller mesh in certain areas → makes more accurate → little more difficult to compute

There’s this video that explains how to locally refine your mesh.

Solidworks FEA Meshing Techniques Tutorial

If you’re adding this into your report, just add some screenshots of where you’re adding the refinements.

Mesh Convergence

Run 5 simulation with progressively smaller meshes. The idea is that has you decrease the size of the mesh the nodes will approach the size of atoms, basically resulting in the most accurate simulation possible.

Here’s a useful table to through stuff into!

Node Size

Max Stress

Location

Node Size

Max Stress

Location

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In the location column try to add in a screenshot of the part! - Easier than using words

Also throw in a graph to show the relation between the two, probably easiest to do that in Excel. If you do it in Excel, attached the document to the page then!

Right click on mesh, the left click on create mesh.

The drop down mesh parameters and you’ll see the size of the mesh.

When you have a finished simulation

Results

Nothing too complicated here, just add some screenshots of the part in different views. I’m mainly looking for the stress, but if you feel there’s different results you want to show (like displacement). Feel free to add in those screenshots, but be sure to label them.

Recommendations

This is where the real engineering work begins! Here I want you to make some recommendations on what needs to change on the part to make it better.

At the end of the day we need the part to pass, that’s the minimum requirement. If it doesn’t pass, then everything should be able how to get the part to pass.

But if the part passes, then we want to optimize the weight of the part. The easiest way to do it is by locating the areas with low stress and removing them. In general, removing the areas with low stress will increase the stress in other areas, so there is a minimum amount of material that needs to be in the part.

So, take some screenshots and highlight the areas where you want me to remove some material.