Nastran In CAD – Critical Buckling Value


Nastran In CAD can analyse a system for Buckling.  There are a couple of steps to get your final result but the first step is to find the critical buckling value and compare it to the yield strength of your material.  If it is lower than the yield strength then your part has buckled and you need to think of about redesigning the part or modify it to compensate for the buckling effect.

Firstly we will create an analysis in the Nastran In CAD environment.  The type of analysis that we will create initially is linear buckling.  This will give us our buckling Eigenvalue which when multiplied to our initial force will indicate the value at which the buckling will occur.

As per usual, apply your materials and create your Idealization.  This would either be a solid, shell or linear.    Apply your loads and supports and then create a mesh for the part or assembly.

Once this is done run the solution for your analysis.

Once your analysis has solved successfully you will notice that there are no immediate results visible in the browser.  This is the correct behavior for Nastran In CAD.  Right click on the results heading and click on edit.

Under sub-cases in the top left hand corner of the plot dialog box you will notice that there is an Eigenvalue that has been generated.  This value is the multiplier to your initial force that you applied for when the object will buckle.  In this example I applied a force of 35000 N therefore the object will buckle at 35000 N x 2.94 = 102 900 N.

You can then take this value into your next analysis which would be a non linear buckling analysis to further the study into the buckling.