Smoosh the horizontal Nalgene

It was only a matter of time. At the end of the vertical Nalgene smoosh, there were hints of more to come as I had unearthed another Nalgene of the same make (and with fewer stickers).

deformed nalgenes

they never stood a chance.

We learned from the previous experiment that, in a test of vertical compression, the threaded top failed at ~700 lbs and the main body lasted to ~1400 lbs before buckling. What sort of force could a horizontally oriented Nalgene cylinder resist? Arches and…circular things are supposed to be strong, right? “John” thought it could hold up to at least 3,000 lbf. This round we recorded the time-resolved applied load as the machine compressed at a rate of 0.5 in/min. The photo sequence below shows the Nalgene over time.

nalgene compression sequence with plots

Nalgene compression at at selected times during the experiment, and corresponding pound-force being applied at that time. a) initial, b) after main body failure, c) continuing compression, and d) plastic on plastic contact. I obviously made the value labels tiny so as not to ruin the surprise.

Once again, the main body failed at 1400 lbf! The inner shadows visible in b and c are, I think, the same indentations visible in the first photo of this post. For stability, we placed the Nalgene on a metal plate with a small groove (just visible in b above). These cut into the bottle (see below) but I don’t think affected the structural integrity.

Two parallel groove indentations (arrows) where the bottom metal plate was notched for stability (visible in image (b) in the sequence above)

Two parallel groove indentations (arrows) where the bottom metal plate was notched for stability (visible in image (b) in the sequence above)

The bottle mouth, hanging over the edge of the plate, bowed out as well.

nalgene top side view

bowing out of the Nalgene mouth, which was not constrained by the plates. Space Lego man inside the bottle for scale.

After a certain amount of flattening and spreading-out, part of the bottle was hanging over the edge of the plate. Thus one side (left in photo below) was more compressed than the other (right), resulting in a wedge shape. You can also see the indentations where it hung over the edge. “John” informed me one of the plates can pivot a couple of degrees – hence the need for the use of a notched plate for stability – which likely also contributed to differential pressure applied across the bottle.

nalgene bottom deformed

It was tough to eyeball where to place the Nalgene.

One of our concerns was the effect the two bolts securing the top plate might have on the test. It turned out not to be an issue. One of the bolts did come into contact with the top lip, but only caused a slight indentation. Disaster avoided!

nalgene_bolt_caused_notch

My very helpful scale is pointing out the notch created when the bottle lip was in contact with an anchoring bolt.

This test was a little less dramatic than the first, with no cracks or crazy shapes, and we knew it was not going to shatter. The most surprising find was that major structural failure occurred under the same load of 1400 lbs. Unfortunately I am now all out of these Nalgene bottles. Experimentation over?

Low-T, high-P rheology of a Nalgene water bottle

Callan’s post on the rheology of an overheated water bottle reminded me of a little experiment from before I started this blog. I had not thought to share the results with y’all until now!

This post in a nutshell: undeformed and deformed Nalgene water bottles

This is, of course, all John’s idea. “John” is in the engineering side of our department, and he does a lot of work with concrete and steel to accomplish undoubtedly ingenious engineering…schemes. One piece to the puzzle lies in designing buildings and bridges that do not break or fall down at the drop of a hat. This involves much testing of tension and compression yield strengths of industrial materials; tests which utilize the awesomely named universal testing machine (UTM) and other implements of destruction. Our UTM can apply a force up to 600,000 pounds (300 tons; about the weight of a Boeing 747). Continue reading