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1-Visitor
March 15, 2016
Question

How to make a analysis on oak

  • March 15, 2016
  • 14 replies
  • 3840 views

Dear,

 

I am trying to make a analysis of a oak beam in Creo ptc.

I draw the beam, made a new material with the oak properties and give it constraint and loads.

But I get strange result out of it if I compare it with other programs like Inventor and Ansys.

 

I hope somebody can help me.

 

Thanks beforehands

 

Kinds regards

 

Oona


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14 replies

1-Visitor
March 15, 2016

You will need to give more information that this, if you want us to help you!

What does your model look like? Ideally you can maybe share your model so we can have a look at it.

What is strange about the results?
What is the difference with Inventor / Ansys?

odeclerck1-VisitorAuthor
1-Visitor
March 15, 2016

 

It is a oak beam of 48x200x8000mm there are 4 forces on it.

2 in the middle of 557.5N and 16N

And 2 remote forces at 48x200x3400mm and 48x200x4600mm of 1225.6N

 

The result with Ansys is 13mm, with Inventor is 17mm and with Creo ptc 23mm.

This is a quiet big difference.

 

I would like to add my document but I have now idea how.

 

Kinds regards

 

Oona

16-Pearl
March 16, 2016

Without knowing anything more, I would guess that the models created in ANSYS and Inventor are too stiff because the number of elements used are too small. Try increasing the number of elements in your beam to see if the result approaches the Simulate model.

Chris

15-Moonstone
March 16, 2016

Hello

Cannot open your file, you are with a student version.

Kind regards.

Denis

odeclerck1-VisitorAuthor
1-Visitor
March 16, 2016

Dear

How can you increas the number of elements in Creo PTC simulation?

I only have a student version available.

Kinds regards

1-Visitor
March 16, 2016

I cannot open your model, but if I interpret your data correctly, and use a simply supported beam with E=12.15GPa for Oak Wood, then hand calculations show the max deflection should be about 11.4 mm. 80.8 mm 

Now i'm curious why Creo finds over twice that value.... most likely some modelling error though!

16-Pearl
March 17, 2016

I happen to be very well aware of the operation of these codes, having used ANSYS and Mechanica for over 20 years. In my original post, I suggested increasing the number of elements in the ANSYS and Inventor models (not Simulate) to see if those results will approach the Simulate answer. I have seen this issue dozens of times with beginners getting into FEA and using Mechanica/Simulate and then trying the same model with an h-element code. When they double the elements in the h-code tool, all of a sudden the answer matches Mechanica/Simulate...for a very good reason. Proper training and course work to understand the fundamentals of how FEA codes work should be sought after for anybody wanting to learn how to use FEA. Otherwise, it's a time-consuming way to make funny-looking colored images of parts.

Of course, there are many other reasons why the results are different, this is my first guess without knowing anything else.

1-Visitor
March 17, 2016

I must be misreading because the loads you have don't look like they cancel.

2 in the middle of 557.5N and 16N

And 2 remote forces at 48x200x3400mm and 48x200x4600mm of 1225.6N

Post a free-body diagram.

1-Visitor
March 17, 2016

Check h-Method & p-Method | Everyone is Number One for a better understanding of how the software you are using works and the suggestions being made.

odeclerck1-VisitorAuthor
1-Visitor
March 18, 2016

Dear,

Now the only thing I can do is following a small screen with the step materials, constraints, loads, analysis and view result.

Mine licence does not allow to us the upper toolbar.

Kinds regards