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Author Topic: Why does a flywheel fly apart?  (Read 920 times)

Offline jerrygg38

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Why does a flywheel fly apart?
« on: 11/08/2016 14:21:40 »
Why does a flywheel fly apart?
   From a mechanical engineering viewpoint you can calculate all the forces within a flywheel and determine how fast it can spin based upon the bonding forces. Thus each grinding wheel has different speed ratings in rpm. That is standard. Once we have super strong solid metal or space age carbon fibers, we can achieve very high rotations. Let us assume that we can produce a flywheel that can withstand extremely high velocities. What will make it fly apart?
   We are now left with Einsteinian space time type problems. We are also left with Doppler corrections to these problems. Linear space time has Doppler corrections and the same would be true orbital systems. The high velocity flywheel from a linear perspective would have a lower orbital velocity near the center and a larger velocity near the surface. Even without the Doppler effects, the center of the wheel will shrink but the outside of the wheel will shrink even more in the direction of rotation.
  We then get Einsteinian type forces which press the outer surface closer together and force the entire package to shrink slightly in radius. This causes the flywheel to crack on the outer surface and fly apart. Thus even the best flywheel will be destroyed long before we reach near the speed of light C.
  The Doppler effects when added to Einsteinís regular equations make the situation worse but it is sufficient to see that a variation of special relativity is applicable to a spinning wheel. What do you guys think?


 

Offline William McC

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Re: Why does a flywheel fly apart?
« Reply #1 on: 14/08/2016 02:33:46 »
Why does a flywheel fly apart?
   From a mechanical engineering viewpoint you can calculate all the forces within a flywheel and determine how fast it can spin based upon the bonding forces. Thus each grinding wheel has different speed ratings in rpm. That is standard. Once we have super strong solid metal or space age carbon fibers, we can achieve very high rotations. Let us assume that we can produce a flywheel that can withstand extremely high velocities. What will make it fly apart?
   We are now left with Einsteinian space time type problems. We are also left with Doppler corrections to these problems. Linear space time has Doppler corrections and the same would be true orbital systems. The high velocity flywheel from a linear perspective would have a lower orbital velocity near the center and a larger velocity near the surface. Even without the Doppler effects, the center of the wheel will shrink but the outside of the wheel will shrink even more in the direction of rotation.
  We then get Einsteinian type forces which press the outer surface closer together and force the entire package to shrink slightly in radius. This causes the flywheel to crack on the outer surface and fly apart. Thus even the best flywheel will be destroyed long before we reach near the speed of light C.
  The Doppler effects when added to Einsteinís regular equations make the situation worse but it is sufficient to see that a variation of special relativity is applicable to a spinning wheel. What do you guys think?

I was taught that things set in motion like to travel in a straight line. Which can be evidenced by objects set adrift in space in some direction. They tend to fly in a straight path unless influenced by other forces.

The reason according to my teachings is that movement requires charging of the object, to allow it to travel through what ever medium it is traveling through. Kind of like a meteor creates a lighted area in front of it as it is traveling somewhat towards the sun against the solar wind. Everything according to old school teachings is electricity, the only sub-matter particle in the universe. Matter the hydrogen atom, is made up of a lot, an infinite amount of these particles of electricity. Held in a spherical shape by the formula for a sphere, Pi D^2 and Pi D^3ų6 the formula for the area of a sphere and the volume of a sphere respectfully. The ratio of surface area to volume of a sphere changes as you increase the size of a sphere. The very large surface area of a hydrogen atom, compared to its tiny volume gives ambient radiation the power to bombard the hydrogen atoms that make up all matter and maintain their spherical shape. These same formula limit the size of cell life on earth. By limiting the amount of food and waste that can pass through a cell membrane to feed the cell volume. When you over look these formulas and calculate upon a cube for heat dissipation you can find your reaction or process out of control, because the imaginary spherical shape within a cubical structure or tank, is the calculation despite the tanks shape.

If you try to deflect a small .22 caliber bullet you will notice that it can bend steel to maintain a straight path. Even though you may only be trying to alter its path by one degree. The bullet wishes to continue in a straight line.

The particles in the grinding wheel also wish to maintain a straight path, not a rotational or orbital path around the shaft that powers them.

That is why larger wheels have lower RPM's because the velocity of the material in the outer most part of the wheel, is moving faster than the area closest to the shaft driving the wheel. The materials in the outer most part of the wheel have more velocity, and therefore more potential power to continue in a straight path. Eventually with enough force to repel against ambient radiation holding the matter together, if spun fast enough.

High pressure, extreme velocity propulsion systems that use a Venturi to create thrust, can actually act like a gyro system, or fins on a rocket in the atmosphere, to stabilize the ship. The Lunar module used this Venturi method of propulsion, and it would stabilize the craft as it lifted off. Many nay sayers of the Apollo missions were convinced that there was no way a craft without air and fins could possibly accelerate at very high rates without losing control. It was the Venturi effect that allowed it.

Imagine a large flat roadway, 100 yards long, suspended in the center. And a car driving over the roadway. If you were to spin the roadway keeping it level to the earth, but rotating it either clockwise or counterclockwise, at the pivot point, as the car drove over that point. The car would actually screech its tires, loose traction, perhaps have to correctively steer the vehicle to keep it between the lines on the road, keep it moving parallel to the roadway. Things move in a straight line unless you apply another force to them.

Sincerely,

Wiliam McCormick


« Last Edit: 14/08/2016 02:36:15 by William McC »
 

Offline alancalverd

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Re: Why does a flywheel fly apart?
« Reply #2 on: 14/08/2016 09:28:42 »
"Modern" textbooks insist that there is no such thing as centrifugal force.

This is a great comfort to mechanical engineers, who can now spin wheels as fast as they like without the tyres coming off or the grinding wheel bursting.

It is however worrying to know that the tension you feel when you whirl an object around on a string, or the phenomenon that makes you black out in a tight aerobatic turn (just before the wings fall off)  is a figment of your outdated imagination.
« Last Edit: 14/08/2016 09:31:34 by alancalverd »
 

Offline evan_au

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Re: Why does a flywheel fly apart?
« Reply #3 on: 14/08/2016 11:16:28 »
Quote from: jerrygg38
determine how fast it can spin based upon the bonding forces
The binding forces are fairly easily calculated by chemists - it is the attraction between electrons of opposite spin, interacting with the positive charge of the positive nuclei.

But this is not nearly enough to achieve relativistic speeds for the rim of a flywheel...

Quote
Once we have super strong solid metal or space age carbon fibers, we can achieve very high rotations
You can work out the tensile strength of carbon nanotubes, and it is extremely high. But in reality:
- it is extremely difficult to produce defect-free carbon nanotubes with specific diameter(s) and length.
- And it is very hard to anchor them to the hub with anywhere near the strength needed to hold them against the centrifugal forces - it might be easier to arrange them as closed loops concentric with the hub?
- The ends of the nanotubes must be capped, so there aren't any reactive loose bonds. In theory, this could be done with a hemispheric geodesic dome of carbon (a semi-buckyball), or by joining the two ends together.
- If the outer rim is to spin at over half the speed of sound, you pretty much need to enclose it in a vacuum
- Non-contact bearings which are sealed against atmospheric pressure are a challenge.
- If it is to be used in a moving vehicle, gyroscopic forces are even more of a challenge for the bearings.
- To deliver energy to the hub efficiently, you want the entire disk to behave as a solid object, not as a bed of waving sea-grass. Some filler must seal all the spaces between the carbon fibers, and be anchored firmly to the fibers
- But unfortunately, the graphite-like surface of carbon nanotubes is very slippery, so the filler will have only weak Van der Waals forces to achor it; not so good for a material which will probably be weaker than the carbon fibers themselves.

After all of these challenges, some nanotubes will be under more stress than others due to shrinkage of the filler or temperature variations, and these fibers will take a disproportionate amount of the load. These will fracture first. This places all that stress on the next-most-stressed fibers, which with then rupture, setting off a chain-reaction which causes the flywheel to fly apart if it is used anywhere near the theoretical limit.

In some ways the ductility of metals helps with sharing the load evenly, meaning that you don't need a separate filler. Metals also have a higher density than the air-cored carbon nanotubes, so they can store more kinetic energy at a lower speed.

High-strength flywheels have been tested in motor racing, but they don't have a clear advantage; many teams chose not to use them even when they were permitted.
Some teams seem to prefer fast-charge electrical storage (eg supercapacitors) rather than mechanical storage, see:
https://en.wikipedia.org/wiki/Kinetic_energy_recovery_system#Use_in_motor_sport
 

Offline jerrygg38

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Re: Why does a flywheel fly apart?
« Reply #4 on: 14/08/2016 19:37:07 »
Thanks to all for the good comments.
 

Offline Colin2B

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Re: Why does a flywheel fly apart?
« Reply #5 on: 17/08/2016 14:36:34 »
  We then get Einsteinian type forces which press the outer surface closer together and force the entire package to shrink slightly in radius. This causes the flywheel to crack on the outer surface and fly apart. Thus even the best flywheel will be destroyed long before we reach near the speed of light C.
  The Doppler effects when added to Einsteinís regular equations make the situation worse but it is sufficient to see that a variation of special relativity is applicable to a spinning wheel. What do you guys think?
Doppler effect only affects the EMR from the source it doesn't change the physical characteristics of the object.
Although there are relativistic effects with rotating discs the local observer at the rim does not see stress due to any length contraction so there is nothing relativistic to cause the flywheel to disintegrate.
 

Offline alancalverd

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Re: Why does a flywheel fly apart?
« Reply #6 on: 17/08/2016 17:48:13 »
Particles approaching  a black hole at a tangent will accelerate to near-c before diving into the event horizon, so there's plenty of stuff out there doing relativistic things where gravity is a lot stronger than any chemical bond.
 

Offline Colin2B

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Re: Why does a flywheel fly apart?
« Reply #7 on: 17/08/2016 17:58:34 »
Particles approaching  a black hole at a tangent will accelerate to near-c before diving into the event horizon, so there's plenty of stuff out there doing relativistic things where gravity is a lot stronger than any chemical bond.
Agreed.
If that's what Jerry meant then I'm ok with it, but I still don't understand the Doppler reference.
 

Offline jerrygg38

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Re: Why does a flywheel fly apart?
« Reply #8 on: 18/08/2016 10:52:40 »
Particles approaching  a black hole at a tangent will accelerate to near-c before diving into the event horizon, so there's plenty of stuff out there doing relativistic things where gravity is a lot stronger than any chemical bond.
Agreed.
If that's what Jerry meant then I'm ok with it, but I still don't understand the Doppler reference.
   I always look at the Doppler reference because 40 years ago I studied the Doppler mass experiments from MIT and other universities which were in the Radar research libraries. At that time the results were promising but they were in the margin of error. Unfortunately they were marked secret. So today they probably could produce better results. Yet if I take the geometric mean of simple Doppler equations I get Einsteins equations. So it seems to me that Doppler is correct.
  I was looking for a space time answer and the blackhole discussion seems to fit pretty well. If I calculate how fast an electron goes when it is pushed toward the proton, I get 0.9186C before absorption into the neutron. This is an Einsteinian energy of 0.782MEV. Thus it appears to me that the energy of the neutrino is equal to the Einsteinian energy.
  Thus the neutron is like a little black hole where the electron is absorbed into the proton. However it has this Einsteinian energy and will fly out. Thus the neutron in my opinion is another form of the Bohr atom but quite unstable. It may be that the neutrino did the pushing of the electron into the neutron. But it is interesting in that the hydrogen atom/ neutron is a good example of the conversion of energy to mass and visa versa.
 

Offline Ethos_

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Re: Why does a flywheel fly apart?
« Reply #9 on: 21/08/2016 14:13:27 »
Particles approaching  a black hole at a tangent will accelerate to near-c before diving into the event horizon, so there's plenty of stuff out there doing relativistic things where gravity is a lot stronger than any chemical bond.
Agreed.
If that's what Jerry meant then I'm ok with it, but I still don't understand the Doppler reference.
I suspect Jerry is referring to Lorentz contraction instead.
 

Offline jerrygg38

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Re: Why does a flywheel fly apart?
« Reply #10 on: 21/08/2016 14:43:32 »
Particles approaching  a black hole at a tangent will accelerate to near-c before diving into the event horizon, so there's plenty of stuff out there doing relativistic things where gravity is a lot stronger than any chemical bond.
Agreed.
If that's what Jerry meant then I'm ok with it, but I still don't understand the Doppler reference.
I suspect Jerry is referring to Lorentz contraction instead.
   In my opinion, there should be Einsteinian type equations for orbital motion. An ideal spinning disk would tend to contract in radius as all the surfaces contract.  The outer surface will contract more because it is moving faster. This does not affect an ordinary flywheel because you need to move pretty fast perhaps 0.01C on the outer surface. This should cause it to rip. At the same time if I add a Doppler gravitational field distortion to the atoms of the spinning wheel, this would seem similar to heat and the outer surface of the wheel would tend to melt. Thus it would fly apart. [Alternatively the Doppler variation of the stronger atomic binding fields would destroy the flywheel.]
 

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Re: Why does a flywheel fly apart?
« Reply #10 on: 21/08/2016 14:43:32 »

 

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