I am storing a suitcase full of stuff at my college. At the storage site, I saw how luggage was stacked one on top of another. As some of the suitcases are probably very heavy, and as my suitcase will be stored there for a few months, I am wondering about the correct way to store the luggage to minimize the damage for the suitcases at the bottom of the pile. Should the cases be stacked sideways (as depicted in this image) or should they be stacked with the largest face pointing up (as depicted in this image)? Or would the two storage methods be equivalent? Finally how sturdy should a typical relatively new soft-case suitcase be?
Simple answer: It depends!
In general, in physics, pressure on shorter structures has less chances of bending/breaking them. For exmaple, you can bend a metal stick of 1m length easier than a nail of the same diameter. So if you have pressure coming from above, the shortest edges should be vertical to maximise the resistance against the pressure.
If you have a smaller luggage, the difference in centimeter between the various sides is smaller and therefore it does not matter so much which side it is on. Chances are high that the luggage will lie on top of others, or that luggages on top will be larger and therefore the pressure will not be on a small spot in a large surface but rather covering the whole surface of your luggage and thus the pressure is on the outer frame which is more stable than the center of the surface.
However if you have a very large (and thin) luggage, you might not want to lie it on the larger surface since chances are high that a luggage lying on top is smaller and therefore not putting pressure on the more stable outer edges of the frame but on the softer center of the cover. The luggage might deform over time.