- #1
In summary, the goal of this project is to find a replacement for a metal spring that has the same efficiency in bouncing an object that's hung by the spring. Any input of a kind would be valuable. Bungee cords come to mind. They are probably not quite as 'efficient' as a metal spring if I understand what you mean by 'efficient.' Fused quartz or glass is possible. Maybe you can tell us why you need to avoid metal. Springs can be made with plastic. Any alternatives you know for metal spring? The idea is to find a replacement for a metal spring that has the same efficiency in bouncing an object that's hung by the spring. Any input of a kind would be valuable.
- #2
Baluncore
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Welcome to PF.
What is the weight of the suspended mass ?
What is the weight of the suspended mass ?
- #3
aibolot
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It varies between 5-10 kgBaluncore said:
- #4
Dullard
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'Bungee' cords come to mind. They are probably not quite as 'efficient' as a metal spring if I understand what you mean by 'efficient.'
- #5
Baluncore
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Fused quartz or glass is possible.aibolot said:
Maybe you can tell us why you need to avoid metal.
- #6
anorlunda
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Springs can be made with plastic.
- #7
berkeman
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Welcome to PF.aibolot said:
Is this for a school project perhaps? If so, can you post the full project requirements statement? Thanks.
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aibolot
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Thanks, I'll look into this!Dullard said:
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AGAIN, why do you need to avoid metal?aibolot said:
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aibolot
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I'm working on a project where I need to hang an object which needs to move vertically as you pull it down. The longer it bounces the better it is. At this point, there is no clear reason to avoid metal - just looking for alternatives if any. I hope this is clear.Baluncore said:
- #11
some bloke
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So this is for some sort of competition to see who can make the longest lasting linear oscillator using nothing but potential energy (sprung potential vs gravitational)?
You want to minimise your losses. Make the weights sit in an aerodynamic chamber, or better yet, a vacuum.
I don't know whether it would be more efficient to use a longer spring which is stiffer or a shorter one which is stretchier. on one hand, the longer stiff spring will flex less so generate less heat per volume, but the shorter one has less volume so the losses may balance out. My gut says the longer, stiffer spring would be more efficient, but gut feelings don't always work in Physics!
Make sure that any and all moving parts are well lubricated and not losing you momentum (EG don't use a bolt in a hole if you can use a bearing or a bush).
More info on what exactly you need will yield better answers. what does it have to do - what are the criteria. You don't have to reveal the purpose of the design, just the criteria you consider a success.
For minimal friction, you could suspend the weight on a pulley strap slung over a bicycle wheel, so you get full use of the bearings and can adjust the leverage applied by the spring by adjusting the distance between the wheel bearings and te spring affixing point, so that you can experiment with it to achieve your best results without needing to buy lots of springs!
You want to minimise your losses. Make the weights sit in an aerodynamic chamber, or better yet, a vacuum.
I don't know whether it would be more efficient to use a longer spring which is stiffer or a shorter one which is stretchier. on one hand, the longer stiff spring will flex less so generate less heat per volume, but the shorter one has less volume so the losses may balance out. My gut says the longer, stiffer spring would be more efficient, but gut feelings don't always work in Physics!
Make sure that any and all moving parts are well lubricated and not losing you momentum (EG don't use a bolt in a hole if you can use a bearing or a bush).
More info on what exactly you need will yield better answers. what does it have to do - what are the criteria. You don't have to reveal the purpose of the design, just the criteria you consider a success.
For minimal friction, you could suspend the weight on a pulley strap slung over a bicycle wheel, so you get full use of the bearings and can adjust the leverage applied by the spring by adjusting the distance between the wheel bearings and te spring affixing point, so that you can experiment with it to achieve your best results without needing to buy lots of springs!
- #12
berkeman
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No reply to my question by the OP, so I've moved the thread to the schoolwork forums now with an expiring redirect left behind in General Engineering.berkeman said:
- #13
anorlunda
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Sounds like traditional clockmaking to me. My father repaired and collected clocks. He had hundreds of clocks that might compete in your competition.
Is electrical or chemical potential energy eligible?
Be alert for hidden sources of energy such as changes in barometric pressure or temperature, or tidal forces, or tectonic motion, or wobble in Earth's orbit.
If you want to be modern and exclude all those old clocks, I suggest doing some research to find the longest running clock from history. Set that time as the floor. Entries must surpass that time to qualify. (with 90 seconds of research found 14 days)
p.s.: Wake me up when the winner is announced.
Is electrical or chemical potential energy eligible?
Be alert for hidden sources of energy such as changes in barometric pressure or temperature, or tidal forces, or tectonic motion, or wobble in Earth's orbit.
If you want to be modern and exclude all those old clocks, I suggest doing some research to find the longest running clock from history. Set that time as the floor. Entries must surpass that time to qualify. (with 90 seconds of research found 14 days)
p.s.: Wake me up when the winner is announced.