Learning Forum

[Ramida Rungroj]

I wonder what is the mode in Eigenvalue Buckling and how it is essential. The initial number of modes is 2 but my professor told me I must change it to 10. So these are my questions:

1. What is mode and how is it important?
2. If I analyse 10 modes and the load multiplier is negative from mode 1 to 7 but positive for mode 8 and 9, what does it mean?
3.  

[peteroznewman]

The mode shows you the buckled shape. It is important because it shows you which way the structure moves.

A negative sign on the load multiplier simply means the structure will buckle when the load is applied in the opposite direction.

Sometimes you have no interest in buckling under loads in the opposite direction because that could never happen. In those cases, you can instruct the solver to exclude negative load multipliers.  In other cases, you may be interested in the smallest load multiplier both positive and negative.

[Ramida Rungroj]

if I get a result like this it means that my structure will not be buckling at all, right?

[peteroznewman]

This result shows that the structure will buckle when a load that is 977 times larger than the load applied in Static Structural is applied in the opposite direction.

[Ramida Rungroj]

thank you so much! I will ask next question about vibration in the new post