Inelastic Buckling/Buckling in short columns

In summary: It can also be used for inelastic buckling with the appropriate modifications.In summary, the conversation discusses the calculation of buckling force for short columns. It is mentioned that global elastic buckling theory is not useful for predicting material failure in short columns. To determine if a column is short, several factors such as material, loading, support, buckling length, and slenderness ratio must be considered. The use of Johnson's equation is also mentioned, which applies to inelastic buckling and requires the tangent modulus. It is clarified that buckling should still be considered for short column scenarios and Johnson's formula can be used with modifications for inelastic buckling.
  • #1
roanoar
13
0
Hey I was wondering how you're supposed to calculate the buckling force for a short column. Is there even a way? If there is, is it accurate and how do you use it? And finally how do you know when to use it?
 
Engineering news on Phys.org
  • #2
If the column is "short" (below slenderness ratio limit) there is no global elastic buckling before the material yields, so global elastic buckling theory will not be useful for predicting material failure.

To verify whether a column is "short" or not, you must know the material, how it is being loaded, how it's being supported (fixed, fixed-fixed, pinned-fixed, pinned-guided...), the effective buckling length, the least section's radius of gyration and the limiting slenderness ratio for your beam-column in the design code you are working with.
 
  • #3
That's interesting so I guess I shouldn't be looking at buckling for these short scenarios. I have calculated all the things you mentioned and have verified it is short. I was simply looking at buckling originally because I came across something called Johnson's equation which supposedly can solve buckling for short beams. But it requires a tangent modulus and this threw me off.
 
  • #4
Most engineering designs are within the elastic limit and Euler's critical buckling load is included here. Johnson's approach applies to inelastic buckling, where the material already yielded with little strain or shows no significant elastic behaviour, hence the need for the tangent modulus.
 
  • #5
roanoar said:
So I guess I shouldn't be looking at buckling for these short column scenarios.
You should be looking at buckling. You were right to look at that.

The Johnson formula applies to short columns. Notice the peak stress in the Johnson formula is the compressive yield strength, Scy. Hence, the Johnson formula prevents inelastic behavior. Furthermore, you divide the Johnson formula by a factor of safety, making the peak stress below the yield strength. Also, the Johnson formula uses modulus of elasticity, not tangent modulus.
 
Last edited:
  • #6
nvn is right, you can apply Johnson's approach to short columns, but it is not limited to this condition.
 

Related to Inelastic Buckling/Buckling in short columns

1. What is inelastic buckling in short columns?

Inelastic buckling, also known as plastic buckling, is a phenomenon in which a column fails due to plastic deformation rather than elastic deformation. This occurs when the load applied to the column exceeds its critical load, causing it to buckle and deform permanently.

2. How does inelastic buckling differ from elastic buckling?

Elastic buckling occurs when a column reaches its critical load and starts to deform elastically, but it can still support the load. In contrast, inelastic buckling occurs when the load exceeds the critical load and the column deforms plastically, leading to failure.

3. What factors affect the critical load for inelastic buckling in short columns?

The critical load for inelastic buckling is affected by several factors, including the material properties of the column, the column's cross-sectional shape and dimensions, the support conditions, and the type of loading applied to the column.

4. How can inelastic buckling be prevented in short columns?

Inelastic buckling can be prevented by ensuring that the load applied to the column does not exceed its critical load. This can be achieved by using appropriate column design and selecting materials with high strength and stiffness.

5. What are the consequences of inelastic buckling in short columns?

The consequences of inelastic buckling in short columns can be severe, as it can lead to the collapse of the structure. It can also cause significant damage and compromise the safety of the surrounding area. Therefore, it is crucial to consider inelastic buckling in the design and construction of short columns.

Similar threads

Buckling Simulation: Questions & Answers
    • Mechanical Engineering
Replies
1
Views
1K
Method to decide if calculating buckling failure is compulsory or not?
    • Mechanical Engineering
Replies
1
Views
882
Column under a concentric axial load (Buckling)
    • Mechanical Engineering
Replies
7
Views
5K
Mechanics of a front wheel on a bicycle
    • Mechanical Engineering
Replies
7
Views
1K
Column buckling in a pin jointed structure
    • Mechanical Engineering
Replies
1
Views
1K
COMSOL: stress on a sensor, how to use infinite element domain?
    • Mechanical Engineering
Replies
1
Views
797
Column buckling under axial+transverse combined load
    • Mechanical Engineering
Replies
2
Views
2K
How to Calculate how much a column buckles?
    • Mechanical Engineering
Replies
3
Views
1K
Subsea Pressure Housing Design – Wall Thickness for Stress & Buckling
    • Mechanical Engineering
Replies
13
Views
3K
Self Buckling Initial conditions
    • Mechanical Engineering
Replies
1
Views
829

Hot Threads

Recent Insights

Back
Top