FRP Column Buckling
FRP Column Buckling
(OP)
I'm analyzing a beam-column according to ASCE's Standard for Pultruded FRP Structures. The material has a flexural modulus of ~4,300 ksi and a compressive modulus of ~2,100 ksi. Given the mechanics of buckling (axial load + lateral deflection -> bending -> more deflection ->more bending) it seems like the flexural modulus should govern buckling. The standard specifies that compressive modulus should be used. Does anyone have insight on why compressive modulus is used?






RE: FRP Column Buckling
For a beam column, the moment creates a tension side and compression side. Therefore some of the FRP will be in compression.
RE: FRP Column Buckling
The question is that since Euler buckling is caused by a positive feedback loop involving increased bending, why the bending modulus isn't the specified modulus used in design.
I have an inkling that for most commercial FRP sections there is only a small difference in E_compression and E_flexur, so it wouldn't really matter. However, in my case it's a factor of 2. So, I'd like to get a better handle on why E_compression is used.
Hope this explanation is more clear.