[Dynamic Simulation] Hydraulic Piston constrain problem

[nponcet]

Hello, I am trying to simulate the mechanism of a hydraulic cylinder to lift a safety guard for a machine. I need to determine the maximum force required to operate the mechanism and then export that data into a finite element simulation to analyze the pin that connects the cylinder to the rotating guard.

There is a YouTube video that can serve as a reference for what I am trying to achieve: https://www.youtube.com/watch?v=cuYWvjYdIms&ab_channel=TheM2Team

However, when I am in the assembly environment, the mechanism works fine. When I switch to the dynamic simulation environment to find the forces, I encounter a "over-constrained 1 degree" warning. I have checked my assembly multiple times and tried everything to avoid this error, but I cannot figure out what might be causing it.

I am attaching a video of the operation. I would greatly appreciate it if you could help me analyze this issue so that I can complete the necessary calculations to ensure the proper functioning of the equipment.

[JDMather]

@nponcet 

Can you Attach your assembly here? (But I will be away from my Inventor machine till next week too take a look.)

My guess is that you have a Revolution Joint at both ends of the cylinder/piston assembly.

You should have one Revolution Joint, one Prismatic Joint and one Point-Line Joint.

Revolution Joint permits the rotational DoF.

Prismatic Joint permits the translational DoF.

Point-Line Joint permits translation DoF (limited by Prismatic Joint) and rotational DoF (twisting limited by Prismatic Joint).  All of this is covered in the Wasim Younis book.

[nponcet]

Okay. It seems I've managed to eliminate the "overconstrained" error following your recommendations and instructions. The image shows the suggested connections, and I've also determined the maximum force needed. However, when trying to export the pin connecting the cylinder shaft to the movable guard to FEA, Inventor throws an error, stating the component must be flexible. I've tried various approaches but can't select that component for finite element analysis. What might be wrong with my assembly, and how can I perform the FEA simulation? As you can see, it's a fairly simple assembly.

 

 

 

[Frederick_Law]

Flexible assembly:

https://help.autodesk.com/view/INVNTOR/2023/ENU/?guid=GUID-12FB3D4E-C321-42C3-9CB0-71853B0798AB

[nponcet]

I have worked with flexible assemblies before. However, when trying to export to FEA, I still encounter the same error. What could be the issue? Is it possible that the assembly includes welding? I only need to perform FEA from the dynamic simulation to complete my project.

 

 

[Frederick_Law]

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@nponcet wrote:

What could be the issue? 

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No idea from screenshots.

JD can check your files next week.

[JDMather]

@nponcet 

Show image of the relevant sub-assembly expanded (click the + symbol).

You might need to right click on the component select Component >Promote.

[nponcet]

Mmmm, I haven't been able to grasp it well. I'm going to attach the file in question so that you can review it. The component of interest for conducting the FEA analysis is the one I am pointing out.

I performed the connections in the dynamic simulation as you suggested.

I just need to perform the FEA analysis of that component, and my project would be completed. As I mentioned, Inventor is still reporting the following error:

I would greatly appreciate it if you could help me.

[JDMather]

@nponcet 

I don’t own a license to a rar extractor software.

I only own legal license to Windows OS on my clean machine for zipping/extracting compressed files.

[nponcet]

Ok. I’m sending you the file again in ZIP format.

[nponcet]

Hello, good evening, could you check the files I attached?

[JDMather]

@nponcet 

Model that part as a standard part (not weldment - only for the purpose of this analysis).

Place the part at the top level of the assembly.