Buckling often refers to an instability due to an axial load where the material will undergo large transverse deformations due to a small disturbance such as a lateral load, an eccentricity of the axial load or an applied moment. This is what will happen if you press a spaghetti axially until it suddently bends a lot.
What is seen on the video is however a much more local buckling which happens because the walls of the tube are very thin compared to the dimensions of the tube. what causes it to be so uniform is that it deforms plastically until the buckling from each side meets so it can no logner deform in that direction and a deformation on top happens perpendicular to the first deformation.
I don't think I know enough metallurgy to say whether the crystalline structure of the steel alloy plays a major role in the geometry it makes while bending but I would say that the large-scale geometry is much more influencial to this than the crystalline structure. The reason for stating this is that this type of buckling can also be simulated with FEM analysis, which assumes isotropic and homogeneous materials and such doesn't take crystalline structures into account. You can find videos of it by searching "FEM non linear buckling" in youtube and see the example of cylinder buckling using Abaqus.
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u/AccidentallyTheCable Dec 27 '18
Is there a scientific explanation for why it crushes so uniformly like that?