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Critical Buckling Load
Posted 04.05.2011, 18:25 GMT-4 Structural Mechanics Version 3.5a 2 Replies
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I am new to Comsol and am trying to measure the critical buckling load for a beam.
I started with 2D Euler (In-Plane Euler Beam), draw a rectangle (40nm by 1.2um), fix the bottom and apply a downward load to the top, put in material properties and beam thickness (40nm), mesh and solve. (sometimes constrain points on the top of the beam so the beam acts as a fixed/pinned with no movement in x, only y)
A few questions:
Will increasing the load cause the beam to buckle in this analyse?
How can I plot a load vs displacement to find the critical load?
Do I need a slight side load or will the slight variation in the mesh be enough?
The plan is to see how the number compares with basic theory and then make the model more complicated. So far I have seen the eigenvalue shapes but have no idea on how to get the critical load out.
Thanks in advanced,
I started with 2D Euler (In-Plane Euler Beam), draw a rectangle (40nm by 1.2um), fix the bottom and apply a downward load to the top, put in material properties and beam thickness (40nm), mesh and solve. (sometimes constrain points on the top of the beam so the beam acts as a fixed/pinned with no movement in x, only y)
A few questions:
Will increasing the load cause the beam to buckle in this analyse?
How can I plot a load vs displacement to find the critical load?
Do I need a slight side load or will the slight variation in the mesh be enough?
The plan is to see how the number compares with basic theory and then make the model more complicated. So far I have seen the eigenvalue shapes but have no idea on how to get the critical load out.
Thanks in advanced,
2 Replies Last Post 05.05.2011, 14:36 GMT-4
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Posted:
1 decade ago
If you do a linear buckling analysis you should get the buckling load (in the form of a load factors) and buckling mode shape. In this case you do not need any load or mesh variation to disturb the symmetry. If you do a stationary analysis then you need that perturbation (via load or geometry) to disrupt the symmetry. This type of analysis will also get you the post-buckling response of the beam.
There is a good COMSOL verification example called “Large Deformation Beam” that demonstrates the post-buckling stationary analysis, and another example called “Various Analyses of an Elbow Bracket” that demonstrates the linear buckling analysis.
Nagi Elabbasi
Veryst Engineering
There is a good COMSOL verification example called “Large Deformation Beam” that demonstrates the post-buckling stationary analysis, and another example called “Various Analyses of an Elbow Bracket” that demonstrates the linear buckling analysis.
Nagi Elabbasi
Veryst Engineering
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Posted:
1 decade ago
Nagi,
Thank you! I am still working through some issues but the large deformation beam is very helpful.
I might ask some more questions after a couple of days.
Swan
Thank you! I am still working through some issues but the large deformation beam is very helpful.
I might ask some more questions after a couple of days.
Swan