Negative buckling lengths and coefficient for buckling length

Grasshopper Karamba3D
1

Hello,

I noticed that if we ask Karamba3D to automatically define buckling lengths for buckling in Y and Z, it gives negative length. Can someone please explain a reason behind it or am I missing something here? And is it correct that k (coefficient for buckling length) is considered 2 if member’s one end is free or else it is 1 regardless of fixed or hinged condition, which would make it conservative for fix-fix and fix-hinge condition.

Looking forward to your reply.

Best Regards
Anand Shah

2

Hi, you can refer to this for more information on buckling length calculations in Karamba: 3.1.12: Disassemble Element - Karamba3D 2.2.0

1 Like
3

Hi Matthew,

Thanks for the help. I went through the documentation (3.6.8) and I think it says somewhat similar to what I was assuming. 3.1.12 says that absolute values should be considered for calculations, which makes sense. Nevertheless, I am a bit confused about the highlighted part in the attached image. How could this way of calculating lengths result in negative values?

image
image1333×750 365 KB

Best Regards
Anand Shah

4

Hi,
the negative symbol does not indicate that it has a negative buckling length. It merely indicates that the buckling length has been automatically calculated. You are able to manually override the buckling length of each element using the ModifyElement component.