Inventor FEA - Force Load vs. Bearing Load?

So you are running an FEA analysis in Inventor, and you need to apply a load to a cylindrical face. Do you use a regular "Force Load" or a "Bearing Load"? The answer really depends on how the force should be distributed on the face in question. A bearing load will apply the load in a parabolic distribution, while the force load will be an even distribution.

Huh?

OK, lets take a look at a couple of loading scenarios and the results that each provides. I have used the shock tube from one of the Inventor sample files as an example.

In the first analysis I used a Force Load. Notice that the stress is not centered on the cylindrical face, but rather along its edges as if the cylinder was being stretched.

In the second analysis I used a bearing load. Note that the highest stress is focused on the center of the cylinder. This is much more realistic in a case where a bearing or shaft is acting radially on the cylindrical face.

Contributed by Ben of the CAD Geeks

FEA Convergence - Ensuring accurate simulation results in Inventor

One of the foreign concepts to many people new to FEA is the idea of "Convergence". Convergence is an analytical method that many analysts use to determine the quality of their FEA results. Since FEA uses small elements to solve complex problems, a larger number of smaller elements can sometimes yield more accurate results. But how small is small enough when it comes to element sizes? This is where convergence comes into play. Convergence in Inventor Simulation is actually a series of settings that can be used to automatically make mesh elements smaller, and help determine if results are accurate.

The basic concept is that the mesh will automatically be made of smaller elements and solved until the results of the refined mesh fall within a percentage of the previous mesh. In other words: The smaller mesh is no longer significantly changing the results, and it making it smaller would yield diminishing returns.

In the image below, convergence settings were used to determine the validity of the FEA results. Before using convergence, the stress in the model was calculated to be 5.85 ksi. After turning on convergence (which refines the mesh and makes it smaller), the stress was calculated to be 6.205ksi with only .448% defiation from the previous iteration. This shows us that we can trust our FEA setup and gives us more confidence in our solution.

Contributed by Ben of the Tata Technologies CAD Geeks

Sketches and Simulation

The ability of Inventor to integrate AutoCAD means that previous efforts will not go to waste. Today, we will see this in action as blocks created in AutoCAD almost come to life in the Simulation environment of Inventor Professional.

With the ability to reuse designs from AutoCAD, analyzing concepts in the first few phases of the Digital Prototype becomes a snap.

Video Link:

http://www.screencast.com/t/NzY2ZGY5OT

Blogged by Jason, yet another Cad Geek

May the Force be With You

Let's take a look at how Inventor's Dynamic Simulation can help you determine the amount of force needed to power a mechanical device. In this case, we'll use a windshield wiper mechanism with force put on the blades to act as resistance. We'll determine how much force is needed to adequately propel the device. Let's take a look.

WATCH VIDEO HERE

John with the INCAT CAD Geeks

Copy That... Re-Use Pipe Designs

In another segment of Tube & Pipe design, today we'll look at copying an existing pipe run. There are a couple of options after you make a copy, keep it associate to the original, or make it a seperate instance. In the video we'll take a look at both. Either way, it is quite easy to re-use existing Tube & Pipe runs in your designs.

WATCH VIDEO HERE

John With the INCAT CAD Geeks

Advanced Simulation on Autodesk Labs

I just found the time to check out the new Advanced Simulation technology preview on Autodesk Labs, and I am mightily impressed with the direction Autodesk is taking this technology. You can define all kinds of design variants and design criteria to use in a functional study.

Take a look at this video for an example of this new technology in use:

Watch Video

Contributed by Ben of the INCAT CAD Geeks

Dynamic Simulations to Rendered Animations in Inventor Studio

One of the new features in Inventor Simulation Suite 2009 that I just found the time to learn is the ability to export animation settings from the Dynamic Simulation Environment. These settings can then be used to create a cool rendered animation in Inventor Studio. Check out this video for an example:




Watch Video Here


Contributed by Ben of the INCAT

No Thanks, I'll Defer....with Autodesk Inventor 2009

Updates, that is. If you are using Inventor Professional or Routed Systems to design cable and harnesses, you may want to take advantage of a new feature in 2009. You now have the ability to defer the automatic update that would take place if you were to make an edit. If you have a large assembly or are in the beginning process of your design and not sure where everthing fits yet, this could be a time consuming process everytime you make a change. You also have the ability to defer the BOM length update, further speeding your process time.

WATCH VIDEO HERE

Although this isn't a large assembly, you get the idea...

Another productivity enhancement from our friends at Autodesk.

John with the INCAT CAD Geeks

Working With PCB's.....Importing IDF Information with Inventor Professional

One of the lesser know file types that you can work with inside of Inventor is PCB translater files. These include files of .brd, .emn, .bdf, and .idb.

It is a very simple process to bring the files in and create either a part file or an assembly file.

You have the ability to edit this information also after bringing it into Inventor as well.

Check out my video here:

Enjoy,

Jim.......Another INCAT CAD Geek!

FEA - Reverse Engineered

One of the easliy overlooked features of the FEA module in Inventor Pro's FEA is the ability to reverse engineer the loading scenarios by specifying a known deflection instead of a load. This allows you to determine if a part will be structurally sound at a known deflection, and also allows us to determine the reaction forces at a known deflection.

Take a look at this video for an example of this hidden gem:

Watch Video

Contributed by Ben of the INCAT CAD Geeks