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Buckling analysis

Question asked by Mikael Martinsson on Feb 15, 2012
Latest reply on Feb 16, 2012 by Mikael Martinsson

Hi.

 

I have a long ejector pin for a mold and I have done a static study to evaluate displacement and stress. No problem there.

Since the ejector pins are very long and slender I also want to do a buckling analysis.

The ejector pin is radially fixed 30 mm in the tip and 30 mm in the back end.

There are also 150 mm below the tip where there are a clearance of about 0,5 mm

 

The first thing that i notice when copying fixtures, loads and contacts is that "no penetration" is not available. Why is it so?

This contact was used on the static study to simulate the 0,5 mm radial clearance that we have thru the insert and die holder.

 

I exclude this "no penetration" contact, and run the analysis. The BLF is above 0 but below 1 so buckling can be a problem.

 

I then exchange the contact with a radial fixture similar to the one for the 30 + 30 mm.

The BLF is even lower now. Shouldn't this affect the result in a positive way since the "free length" of the pin is shorter?

 

Perhaps stupid questions and to my defence I have not yet attended the course for this module.

Thank you for your answers.

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