Maximum axial load is proportional to the second moment of area?
Maximum axial load is proportional to the second moment of area?
(OP)
Maximum axial load is proportional to the second moment of area. Thus can we reason that aluminium cans are cylindrical because they have a high second moment of area(mr^2) compared to other shapes(Which gives it a higher max axial load.)?






RE: Maximum axial load is proportional to the second moment of area?
On the other hand, circular cans waste a lot of storage space due to the large gaps between them. Square cans would be more efficient for storage.
BA
RE: Maximum axial load is proportional to the second moment of area?
I'm not aware that the shape of aluminum cans was selected based on axial compressive strength.
RE: Maximum axial load is proportional to the second moment of area?
RE: Maximum axial load is proportional to the second moment of area?
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RE: Maximum axial load is proportional to the second moment of area?
Also, I suspect that axial failure in cans isn't governed by full section buckling. They're too squat. Your failure mechanism is likely local wall buckling.
RE: Maximum axial load is proportional to the second moment of area?
RE: Maximum axial load is proportional to the second moment of area?
https://newtonexcelbach.wordpress.com/2011/07/06/b...
might be of interest.
Long cylindrical tubes do have a higher buckling load than the circumscribed square tube (all other things being equal), but it isn't just a matter of Euler buckling load (see link for more details).
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Maximum axial load is proportional to the second moment of area?
The cylinder will do better in wall buckling, though, so it may turn out to be stronger depending on the loading situation.
RE: Maximum axial load is proportional to the second moment of area?
RE: Maximum axial load is proportional to the second moment of area?
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Maximum axial load is proportional to the second moment of area?
BA
RE: Maximum axial load is proportional to the second moment of area?
The number 1 failure mode is due to dropping or impact. The ideal shape for this is a sphere. Spheres, on impact, deform which reduces the volume. Thus creating an internal pressure. Internal pressures create hoop stress. While a sphere might be great in terms of hoop stress, it is not practical from a shipping, stacking, and storage standpoint.
A cylinder is the compromise. Circles have hoop stress, which is tensile. Squares have bending and flexure. It just so happens that aluminum, which is terrific in tensile strength, is terrible with bending because it deforms so easily.
So, cans are aluminum because of a high tensile material strength, not axial (compression), and cylindrical to take advantage of its tensile strength.
RE: Maximum axial load is proportional to the second moment of area?
http://youtu.be/hUhisi2FBuw
RE: Maximum axial load is proportional to the second moment of area?
That’s can-didly uncanny.