Unsupported rotating ring speed limit - Revision history

Apm: Category:Surprising facts

2026-03-29T20:10:53Z

← Older revision		Revision as of 22:10, 29 March 2026
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	* [[Levitation]]		* [[Levitation]]
	* [[High performance of gem-gum technology]]		* [[High performance of gem-gum technology]]

			[[Category:Surprising facts]]

Apm at 13:55, 21 August 2025

2025-08-21T13:55:00Z

← Older revision		Revision as of 15:55, 21 August 2025
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	For every material formed into a ring there is a maximum tangential speed it can be rotated before the forces rip it apart.		For every material formed into a ring there is a maximum tangential speed it can be rotated before the forces rip it apart.
	This speed depends on the materials ultimate tensile ~~strenght~~ (UTS).		This speed depends on the materials ultimate tensile strength (UTS).
	As it turns out this speed is independent of the size of the ring.		As it turns out this speed is independent of the size of the ring.
	Since in the limits of currently known physics there is an upper limit in material strengths that are achievable there is an upper limit for rotating speed.<br>		Since, within the limits of currently known physics there is an upper limit in material strengths that are achievable there is an upper limit for rotating speed.<br>
	Using one of the materials with highest known UTS (carbon nanotubes) one finds that:<br>		Using one of the materials with highest known UTS (carbon nanotubes) one finds that:<br>
	'''This limit is at about 3000 m/s'''		'''This limit is at about 3000 m/s'''

Apm: typofixes, and added which thermal motion

2025-08-21T13:49:50Z

typofixes, and added which thermal motion

Apm at 13:46, 21 August 2025

2025-08-21T13:46:12Z

← Older revision		Revision as of 15:46, 21 August 2025
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	The maximum speed any physical thing made out of atoms can be ~~spinned~~ is about 3000 meters per second.		The maximum speed any physical thing made out of atoms can be spun is about 3000 meters per second.

	[[File:Gnuplot_scale_typical_accelerations.png\|500px\|thumb\|right\|How natural accelerations grow with shrinking size. Offtopic: To keep waste heat from friction at		[[File:Gnuplot_scale_typical_accelerations.png\|500px\|thumb\|right\|How natural accelerations grow with shrinking size. Offtopic: To keep waste heat from friction at

Apm: /* Related / added High performance of gem-gum technology

2021-07-09T08:27:33Z

Related: added * High performance of gem-gum technology

← Older revision		Revision as of 10:27, 9 July 2021
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	* [[Interplanetary acceleration tracks]]		* [[Interplanetary acceleration tracks]]
	* [[Levitation]]		* [[Levitation]]
			* [[High performance of gem-gum technology]]

Apm: /* Putting things together */

2021-07-09T08:24:11Z

Putting things together

← Older revision		Revision as of 10:24, 9 July 2021
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	Centrifugal forces scale quadratically with size (given constant speeds) <br>		Centrifugal forces scale quadratically with size (given constant speeds) <br>
	That is: Half the size gives quarter the force		That is: Half the size gives quarter the force
	* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 ~~C_12~~ < E_{max} </math> Used: (6) (7) (8)		* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_{1,2} < E_{max} </math> Used: (6) (7) (8)
	'''Result: Centrifugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>		'''Result: Centrifugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>
	That is: Half the size gives the same stress.		That is: Half the size gives the same stress.

Apm: /* Math */

2021-07-09T08:23:29Z

Math

← Older revision		Revision as of 10:23, 9 July 2021
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	That is: Half the size gives the same stress.		That is: Half the size gives the same stress.

	And that is why for one ultimate maximal tensile material strength there is ~~juts~~ one ~~ultimate maximal~~ unsupported rotating ring speed.		And that is why for one ultimate maximal tensile material strength there is just one [[unsupported rotating ring speed limit]].

	== Related ==		== Related ==

Apm: /* Math */

2021-07-09T08:22:18Z

Math

← Older revision		Revision as of 10:22, 9 July 2021
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	* (8) <math> F = m a = m \omega^2 r = (r^3 C_1)((v/r)^2 r)(r) = v^2 r^2 C_1 = F</math> Used: (1) (2) (3) (4)		* (8) <math> F = m a = m \omega^2 r = (r^3 C_1)((v/r)^2 r)(r) = v^2 r^2 C_1 = F</math> Used: (1) (2) (3) (4)
	Centrifugal forces scale quadratically with size (given constant speeds) <br>		Centrifugal forces scale quadratically with size (given constant speeds) <br>
	That is: Half the size quarter the force		That is: Half the size gives quarter the force
	* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < E_{max} </math> Used: (6) (7) (8)		* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < E_{max} </math> Used: (6) (7) (8)
	'''Result: Centrifugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>		'''Result: Centrifugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>
	That is: Half the size same stress.		That is: Half the size gives the same stress.

	And that is why for one ultimate maximal tensile material strength there is juts one ultimate maximal unsupported rotating ring speed.		And that is why for one ultimate maximal tensile material strength there is juts one ultimate maximal unsupported rotating ring speed.

Apm: /* Math */

2021-07-09T08:21:19Z

Math

← Older revision		Revision as of 10:21, 9 July 2021
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	That is: Half the size quarter the force		That is: Half the size quarter the force
	* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < E_{max} </math> Used: (6) (7) (8)		* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < E_{max} </math> Used: (6) (7) (8)
	'''Result: ~~Centiufugal~~ stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>		'''Result: Centrifugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>
	That is: Half the size same stress.		That is: Half the size same stress.

	And that is why for one ultimate maximal tensile material ~~strhength~~ there is juts one ~~ultipate~~ maximal unsupported rotating ring speed.		And that is why for one ultimate maximal tensile material strength there is juts one ultimate maximal unsupported rotating ring speed.

	== Related ==		== Related ==

Apm: /* Putting things together */

2021-07-09T08:20:58Z

Putting things together

← Older revision		Revision as of 10:20, 9 July 2021
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	Centrifugal forces scale quadratically with size (given constant speeds) <br>		Centrifugal forces scale quadratically with size (given constant speeds) <br>
	That is: Half the size quarter the force		That is: Half the size quarter the force
	* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < ~~E_max~~ </math> Used: (6) (7) (8)		* (9) <math> E = F/A = v^2 r^2 C_1 / (r^2 C_2) = v^2 C_12 < E_{max} </math> Used: (6) (7) (8)
	'''Result: Centiufugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>		'''Result: Centiufugal stresses are scale invariant (assuming rotation speeds are kept constant)''' <br>
	That is: Half the size same stress.		That is: Half the size same stress.

← Older revision		Revision as of 15:49, 21 August 2025
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	practical levels it is sensible to slow down at the nanoscale that is as one goes from right to left in the diagram one moves down the lines deviating from the natural scaling law. {{todo\|make a simplified graph with just the red line for this page}}]]		practical levels it is sensible to slow down at the nanoscale that is as one goes from right to left in the diagram one moves down the lines deviating from the natural scaling law. {{todo\|make a simplified graph with just the red line for this page}}]]

	For every material ~~made~~ into a ring there is a maximum tangential speed it can be rotated before the forces rip it apart.		For every material formed into a ring there is a maximum tangential speed it can be rotated before the forces rip it apart.
	This speed depends on the materials ultimate tensile ~~strengh~~ (UTS).		This speed depends on the materials ultimate tensile strenght (UTS).
	As it turns out this speed is independent of the size of the ring.		As it turns out this speed is independent of the size of the ring.
	Since in the limits of currently known physics there is an upper limit in material strengths that are ~~reachable~~ there is an upper limit for rotating speed.<br>		Since in the limits of currently known physics there is an upper limit in material strengths that are achievable there is an upper limit for rotating speed.<br>
	Using one of the materials with highest known UTS (carbon nanotubes) one finds that:<br>		Using one of the materials with highest known UTS (carbon nanotubes) one finds that:<br>
	'''This limit is at about 3000 m/s'''		'''This limit is at about 3000 m/s'''
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	== A practical problem where the limit might matter ==		== A practical problem where the limit might matter ==

	In certain situations the unsupported rotating ring speed limit is a factor that plays a role in the absolute limit of possibly ~~transmittable~~ [[power density]] in [[mechanical energy transmission cables]].		In certain situations the unsupported rotating ring speed limit is a factor that plays a role in the absolute limit of possibly transmissible [[power density]] in [[mechanical energy transmission cables]].

	{{todo\|add the math}}		{{todo\|add the math}}
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	To exceed this rotation speed the ring would need to be supported by an enclosing non-rotating ring.		To exceed this rotation speed the ring would need to be supported by an enclosing non-rotating ring.
	Since the relative motion is about ten times thermal motion at room temperature macroscopically thick (a few millimeters) layers of [[infinitesimal bearing]] are needed that can deal with high levels of stress and deal with a bit of (reversible) strain.		Since the relative motion is about ten times thermal motion of air molecules at room temperature macroscopically thick (a few millimeters) layers of [[infinitesimal bearing]] are needed that can deal with high levels of stress and deal with a bit of (reversible) strain.
	Even then the friction heat might be so high that these '''super-limit speeds''' can be sustained only briefly.		Even then the friction heat might be so high that these '''super-limit speeds''' can be sustained only briefly.

	It is still highly unclear whether a [[levitation\|ultra low friction levitation]] could be ~~archived~~ that would provide enough supporting force.		It is still highly unclear whether a [[levitation\|ultra low friction levitation]] could be achieved that would provide enough supporting force.

	== Math ==		== Math ==

Unsupported rotating ring speed limit - Revision history

Apm: Category:Surprising facts

Apm at 13:55, 21 August 2025

Apm: typofixes, and added which thermal motion

Apm at 13:46, 21 August 2025

Apm: /* Related */ added * High performance of gem-gum technology

Apm: /* Putting things together */

Apm: /* Math */

Apm: /* Math */

Apm: /* Math */

Apm: /* Putting things together */

Apm: /* Related / added High performance of gem-gum technology