Apperance of steel after yielding in compression

[lejam]

Can anyone point me to a picture of the appearance of steel bar when it yields in compression (not tension which simply stretches beyond elastic limit) provided it didn't buckle due to the ties being close together? If you can't find a picture, what describes what happens. Ty.

 

[Ron]

lejam...compressive failure in steel is not so "clean" as tensile failure in steel. The reason is deformation (where and how it occurs).

Ideally, the compression load would be purely axial and the distribution would be even throughout the cross-section. This is rarely the case in practice. Some eccentricity will occur from load application or restraint deformation.

If we could keep the load purely symmetric and axial, failure for ductile steel would follow Poisson's ratio and you would get a "bulge" at the center of the very short column of steel. If the steel is very hard and brittle, the failure would take on more of a diagonal shear mode.

In practicality, for most mild steels, the mode will be a combination of the two with the steel appearing to slide laterally and bulge at the same time. In practice, due to most common restraint failures, the compressive failure mode of steel is buckling.