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High-Speed destruction : Hard-Disc platter warping

Hard-Disc platters are a conveniently sized source of aluminium discs. Diameter is 95mm, mass typically 23.2 grams

disconly_2.m1v (2.5MB) 1000 frames/sec

The distance between the starting position and the top of the pipe is about 175mm. It takes about 3ms to travel this distance, giving a speed of 58m/sec, or 210km/hour (130miles/hour)

wpeBD.jpg (18228 bytes)

wpeBE.jpg (18238 bytes)

3ms later, it hits the top
wpeC1.jpg (18186 bytes)

OK. now what happens when we put something in the way, like a lump of wood..

discwrapwood.m1v (1.6MB) 2000 frames/sec

wpeC2.jpg (15101 bytes)

Slight signs of movement..
wpeC4.jpg (15139 bytes)

500 microseconds later, the disc is wrapped around the wood.
wpeC5.jpg (15035 bytes)

This time, the hub from a hard disc is placed in the centre of the disc : 
disc_hub.m1v (2.8MB) 1000 frames/sec

Although not actively held down, its high mass compared to the disc makes it act like it was, and the disc warps round it.
Once things get going, things get interesting. The whole tube raises up in the air, but I'm not sure if it's a bounce from the downward force of the coil reacting against the mass of the disc+hub, or the impact of the hub on the top of the tube. The coil platform does move down noticeably, but the hub hits the top at about the same time you'd expect to see the bounce, so it's probably a bit of both....

wpeC6.jpg (18779 bytes)

wpeC7.jpg (18992 bytes)

wpeC8.jpg (19169 bytes)

wpeC9.jpg (18796 bytes)


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