Attaching a Plate to a Frame - Stress Analysis

[christian.siciliano9LYM8]

Hello,

I am trying to figure out how to attach a plate to a frame made from frame generator in Autodesk Inventor. So far, I have created a basic frame consisting of 3 rectangular tubular members from the frame generator and a plate by extruding a rectangular section that I sketched. I made the planes from the plate and the frame visible and used them to center the plate by constraining the respective planes to each other. I also constrained the plate face to the frame face. When I hit automatic connections, it is showing that I have 3 bonded connections as I would like to see. However, when I try and run a stress analysis and constrain the bottom vertical members and apply a force load to the plate face, I get warnings and it separates the parts into different components and adds a soft spring. I also tried to constrain the plate via bolted connections and also with welds and am getting similar errors.

I have attached the assembly files: 

Any help would be greatly appreciated. 

Best Regards,

Christian S. 

[jtylerbc]

I don't use Frame Analysis, so I don't know the answer to your question.  But I can point out that no one will be able to open the sample files you included.  You can't just upload the assembly files, as they don't contain the part geometry.  You also have to attach the part files for other people to be able to open the model.

On the forums here, the easiest way is probably to make a zip folder that has your assembly and parts, and attach that zip folder instead of individually uploading all the files.

[JDMather]

*.ipt files?

[christian.siciliano9LYM8]

Good Morning,

Sorry for the late response. I believe that I have figured out the issue. It turns out that the no contacts attached to the body error was referring to the part that I made simply to make the frame. I essentially extruded a rectangle and selected the edges to make the frame. However, that part needs to be suppressed when running a stress analysis or the software will think that you are trying to analyze that part.

However, the assembly with the plate welded to the frame is still giving me an error message saying that welds are not recommended in the stress analysis. Can you not analyze welded connections in a stress analysis? I have attached the .ipt files. 

Thank you everyone for letting me know that I need to attach the .ipt files. 

Best Regards,

Christian

[Cris-Ideas]

You warning actually says:

"model contains welds, consider excluding them from the simulation ...." (or something close, quoting form memory).

So essentially you are advised to reconsider what you are doing, as analyzing welds uses much processing power as your FE model drastically (sometimes) increases in size.

But you can analyze welds just fine if it is what you are after. 

Consider however followings aspects:

1) weld material

2) suppressing contacts between parts welded other than welds. Otherwise your analysis has little sense. 

3) you cannot exclude some welds, you can only exclude or include all, so only model those that you are interested in analyzing.

[christian.siciliano9LYM8]

Cris-Ideas,

Thank you very much for this information.

Best Regards,

Christian Siciliano

[swalton]

Remember that welds produce a Heat Affected Zone in the base metal that may change material properties.  The allowable stress in the HAZ may be different than the parent material.   For example, welding 6061 T6 heat-treated aluminum will revert the base material back to near 6061 T4 properties in in the HAZ.

Inventor's baseline FEA does not have good tools to identify the HAZ around welds, so careful modeling will be required if your engineering judgement (or design code) indicates concern.