Buckling results with different Y.S of the material 2

[sri100880]

I have been running buckling analysis for a tie rod assembly in dyna where in for a material with Y.S of 355 MPa produces a result in the order of 75.8 KN and for a material with Y.S of 500 MPa produces a result of 78.10 KN. With the increase in the Y.S of the material the buckling withstanding capability should increase but it is not proportional to that. Why is it so? We check the load vs displacement graph using Rcforce plot in ls-dyna.

 

[rb1957]

is this an euler column buckling ? driven by E not yield strength ?

but LS-Dyna implies a dynamic problem ??

did you redesign the tie rod (for the higher yield) ? or is it the same design for both materials ?

another day in paradise, or is paradise one day closer ?

 

[Scuka]

Look up basic formulas for buckling. This is the reason why engineers need to to be familiar with formulas instead of just blindly relying on software to spit out the answers. Formulas tell you what affects what.

Buckling is a stability problem, not a strength problem. A rod/column in compression will buckle if its too slender and/or not stiff enough, meaning, geometry and modulus of elasticity are the two main factors.

 

[JStephen]

Failure of compression members will be due to yield at very short lengths, due to Euler buckling at long lengths, with a transition in between where both effects enter in.

 

[HTURKAK]

Euler buckling formula is valid for perfect materials. The codes derates the buckling strength for the imperfections which has correlation with yield strength.

The following excerpt explains the concept.

The following document ( section DESIGN OF COLUMNS ) is attached for ref.

 

[dik]

Excellent attachment, HT...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik