![]() 10/10/2013 at 23:11 • Filed to: None | ![]() | ![]() |
I need some help with an engineering assignment. I'm supposed to find three examples of engineering products that fulfill their design by breaking or deforming plastically. The example he used in class was a staple, because for it to be used, it has to bend out of its normal shape. What else have we got? I thought the canards on the front of the 458 deform at high speeds to increase downforce, but they go back to their normal shape so its elastic deformation instead of plastic.
EDIT: Thanks guys! I've got my 3 things. The winners were glow sticks, pop rivets, and crumple zones in cars. Enjoy this picture as my thanks.
![]() 10/10/2013 at 23:13 |
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Fuses
![]() 10/10/2013 at 23:14 |
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Maybe a ballpoint pen? The spring has to be compressed in order to write.
![]() 10/10/2013 at 23:14 |
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paperclips?
the inside of glowsticks?
yeah i got nothing.
![]() 10/10/2013 at 23:14 |
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Airbags? I know they are only just folded up before use, but its the only thing I could think of.
![]() 10/10/2013 at 23:15 |
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Bumpers, racecar nose cones, basically anything designed to absorb energy.
Alternatively, in the same vein as staples, pop rivets.
![]() 10/10/2013 at 23:15 |
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Packing material like peanuts, bubble wrap, and styrofoam.
![]() 10/10/2013 at 23:16 |
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I'm not a real edumacated boy, but do suspension springs work this way? My thought is that they would be elastic to a point but also plastic? I don't really know.
![]() 10/10/2013 at 23:16 |
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Pop rivets? Fly rods? Springs?
![]() 10/10/2013 at 23:17 |
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Rivets would be a good example.
![]() 10/10/2013 at 23:17 |
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I thought of the glowsticks right after i posted this. I'm adding it!!
![]() 10/10/2013 at 23:18 |
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Drug capsule tablets.
![]() 10/10/2013 at 23:18 |
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But after you use it it goes back to its normal shape. I'm looking for things that stay permanently deformed after use.
![]() 10/10/2013 at 23:19 |
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As DasWauto said, definitely bumpers. Maybe guard rails?
![]() 10/10/2013 at 23:19 |
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Maybe even brushes or bristles. Velcro or the 3M command hooks. It has to be deformed for it to prove it can be removed without damaging the surface.
![]() 10/10/2013 at 23:19 |
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the stop saw breaks itself to save your fingers .
http://www.sawstop.com/how-it-works/
![]() 10/10/2013 at 23:20 |
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When something deforms but can return to its original form, that is elastic deformation. Plastic deformation is the opposite, it doesn't and isn't able to return to its original form.
![]() 10/10/2013 at 23:21 |
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Compressed spring = elastic deformation, not plastic.
![]() 10/10/2013 at 23:22 |
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clay/pottery?
Tamper-proof security labels? They work by being difficult/impossible to remove intact once applied.
![]() 10/10/2013 at 23:24 |
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All of these parts
![]() 10/10/2013 at 23:26 |
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Is that really deformation though? Yes, it deforms but that's not the mechanism; it melts.
![]() 10/10/2013 at 23:27 |
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Not springs - those are elastic.
![]() 10/10/2013 at 23:27 |
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Snap-to-light Flares (although glowsticks are similiar), and crumple zones to prevent a wreck in a car.
![]() 10/10/2013 at 23:27 |
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A vehicles crash structure is designed to do just that. If you never use a staple, it will not bend. Once you use it, it is no good. Just like a crashed car.
![]() 10/10/2013 at 23:28 |
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Try pop rivets. They're a twofer, they expand by deforming plastically, then an internal element breaks.
Also cite-able, any type of freshness seal or packaging seal like the ring on a milk jug or soda bottle.
Further, common wood is installed by breaking and plastically deforming the fibers within.
Finally, if you want to be an ass, you can say tensile test material samples. A product that fulfills its design (either proofing a material or calibrating a machine setup) by failing at a given loading.
![]() 10/10/2013 at 23:30 |
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Ummmm, maybe? I don't know enough much about fuses, just that they serve their purpose by failing.
![]() 10/10/2013 at 23:32 |
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Cheese.
![]() 10/10/2013 at 23:32 |
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Fair point.
![]() 10/10/2013 at 23:32 |
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Airbag, explosive bolts, a bullet? Not sure if they would count.
![]() 10/10/2013 at 23:32 |
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I understand now. How about a "safety seal" on medicine bottles?
![]() 10/10/2013 at 23:35 |
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Firing cap on a bullet.
![]() 10/10/2013 at 23:35 |
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body armor?
![]() 10/10/2013 at 23:35 |
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Rivets came to my mind as well. You could also add crush washers to the list. Maybe filler metals used for welding or soldering?
![]() 10/10/2013 at 23:36 |
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Epoxy as well.
![]() 10/10/2013 at 23:42 |
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Well it's deformation due to electrical/thermal stress, right?
![]() 10/10/2013 at 23:45 |
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There are a lot of things that use plastic/aluminum bolts to shear away safely. You could also look at crush washers/seals and the like that deform to either seal something or to lock a nut/bolt in place.
There are literally thousands of examples all around you. It's tricky because you generally don't even think about what they do in that way. Even engines have gaskets that permanently deform when crushed into place.
![]() 10/10/2013 at 23:46 |
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I don't think this would work since fuses work until they break or melt. I'm looking for something that breaks or plastically deforms and that fulfills the design purpose. Like glowsticks.
![]() 10/10/2013 at 23:55 |
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No, fuses are designed to blow when there is too much current flowing through. They are a safety device to prevent shit like a fire from a short circuit.
Like an electrical crumple zone
![]() 10/11/2013 at 09:15 |
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Smelling salts! You have to break these little chambers to release ammonia. What about pill capsules? Don't they have to dissolve to release meds? Explosive bolts? Sabots on penetrators fired by tanks? Squash head explosives? Explosively formed projectiles? What about WW2 squeeze guns that used a frangible soft iron sabot in a barrel that narrowed in diameter, like a 28mm/20mm anti tank gun. Would a re-entry heat shield work?
My brain is working better today.
![]() 10/11/2013 at 09:19 |
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O_O damn!
Well I suppose all those work except the heat shield as not all of them deform (although I'm sure the case could be made for it).
![]() 10/11/2013 at 09:28 |
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Pull tabs on beverages. Ok I have to stop. This is fun, thanks.
![]() 10/11/2013 at 09:38 |
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Hey that's actually a good one!