Strand7: Buckling Analysis and Predicting Wall failure

[tsanyoto91]

Dear strand7 experts... I need your help

I would like to predict the failure load of a concrete slender wall panel simply supported top and bottom. I modeled my wall in 2D plane and I apply an axial load on the top of the wall and applied moment to represent eccentricity of the load acting on the wall (e=tw/6). I have inputted the stress-strain diagram of the concrete to represent the compression and tensile behaviour of concrete. Initially, I performed a non-linear analysis with load increment; however, this non-linear analysis seems to neglect the buckling analysis which is more critical in a slender wall. How do I predict that my wall fails either due to buckling or material ? If my wall fails due to buckling, how to get max. buckling load ? thank you very much

 

[IDS]

Why do you say "however, this non-linear analysis seems to neglect the buckling analysis which is more critical in a slender wall"?

If you include geometric non-linearity in your analysis, and you have an adequate number of subdivisions of the wall, the analysis will include both buckling and material non-linear effects.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[tsanyoto91]

So what i need to do just tick the non-linear geometry ? Because i thought that the non-linear geometry only covers the p-delta effect. If i remove the bending moment on the wall, the wall only deform downward like a stocky member. It does not show any deflection or bending in the displacement digram.

Btw, how to predict the buckling load in strand7?

 

[tsanyoto91]

Btw, what does it mean by adequate number of subdivisions? How do we know that we have sufficient number of it ? Thanks a lott mannn !!!

 

[jhardy1]

student post?

http://julianh72.blogspot.com

 

[IDS]

So what i need to do just tick the non-linear geometry ? Because i thought that the non-linear geometry only covers the p-delta effect. If i remove the bending moment on the wall, the wall only deform downward like a stocky member. It does not show any deflection or bending in the displacement digram.

Why would you remove the bending moment? To get a reasonable estimate of the buckling load you need to have a model that will induce some bending moment under load, either by applying a bending moment as you have done, or making the load slightly eccentric.

Btw, how to predict the buckling load in strand7?

That's what you are doing. Apply the load in small increments and look at the resulting deflections.

You can also do a linear buckling analysis, but that obviously won't include non-linear materials properties.

Btw, what does it mean by adequate number of subdivisions? How do we know that we have sufficient number of it ? Thanks a lott mannn !!!

Repeat the analysis with an increasing number of subdivisions until it doesn't make a significant difference to the results.

Assuming you have a Strand7 license, you might like to have a look at:

http://www.strand7.com/webnotes/request/?w=ST7-1.20.10.1

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[tsanyoto91]

Hi Doug, thank you for your reply.