Nastran beam does not show reaction forces correct?

[Reshad_Baig1]

Hi 

I have made an model of an IPE-270 beam and added a forces tried but point load and a surface "force" load. The beam is modelled as simply supported but the reaction forces is not correct? 

I have applied a force of 10 kN on the upper face of the model and it shows reaction forces of 2500 N, Which it shouldn't.  Can anyone help?

[John_Holtz]

Hi @Reshad_Baig1 . Welcome to the Inventor Nastran forum.

When I run your model (with Inventor Nastran version 2023.3), I get the correct reaction force sum of 5000 N in each constraint. Please let us know:

1. How are you getting a value of 2500 N from the model you provided? Maybe showing us a screen capture would explain where the 2500 comes from.
2. Which version of Inventor Nastran are you using? Readers with older versions will not be able to view your model.

Just in case this is related to item 1, you should be using Tip 48 in the PDF document attached to my forum post Suggested Reading - Tips and Tricks on the Inventor Nastran forum.

John

[Reshad_Baig1]

Hi John

Thanks for your reply. I have used Inventor 2023. I have attached a png file that shows a max force of 1021 N? Which is not near 5000 N (load 10000N)?

Am i looking at the wrong place?

[John_Holtz · Accepted solution]

You are looking at the wrong place. Tip 48 is the correct place to look. 🙂

Take a much closer look at your result, meaning zoom in to view the reaction force contour plot. 1021 N is the reaction force in 1 node. What are the reaction forces is the dozen of other nodes that are constrained?

You are generally not interested in the reaction force in individual nodes (unless using beam elements). What most people are interested in is the sum of the reaction force from all the nodes in the constraint. According to Tip 48, you should right-click on the constraint in the Model Tree and look at the SPC Summation.

John

[Reshad_Baig1]

Hi John

Thanks again! Do have any possibility of hiding the maximum stresses around the edges? I want to know the max von mises in the beam excluding the edges?

[John_Holtz · Accepted solution]

Hi,

You are not going to get the Max marker to so a value other than the point with the maximum. The best suggestion is to edit the contour ("Results > Options" from the Ribbon), click the Contour Options tab, and click "Specify Min/Max" to enter a range that you would like to see in the color legend.

John