Difference between revisions of "Form closure"

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(also called: shape locking, positive locking, positive closure, ...)
 
(also called: shape locking, positive locking, positive closure, ...)
  
== Usage against thermal Van der Waals bond breakage in the low nanoscale - hirachical locking ==
+
= Usage against thermal Van der Waals bond breakage in the low nanoscale - hirachical locking =
  
 
When the contacting area of two [[diamondoid molecular element|building blocks]] is made smaller then they wont stick together as strong as before.
 
When the contacting area of two [[diamondoid molecular element|building blocks]] is made smaller then they wont stick together as strong as before.
Line 10: Line 10:
 
A nice thing is that with linear rising contact area breakage probability for the VdW-bond falls exponentially thus areas that will never break are quickly reached.
 
A nice thing is that with linear rising contact area breakage probability for the VdW-bond falls exponentially thus areas that will never break are quickly reached.
  
=== Hierarchical locking ===
+
Shape locking might be especially important for high temperature applications where small contact areas become insufficient to hold things together.
 +
 
 +
== Hierarchical locking ==
  
 
To prevent [[diamondoid molecular element|building blocks]] from falling apart by accident one can chain shape locking together.
 
To prevent [[diamondoid molecular element|building blocks]] from falling apart by accident one can chain shape locking together.
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Used can be:
 
Used can be:
 
* Van der Waals sticking with sufficient surface (and back-volume density)  
 
* Van der Waals sticking with sufficient surface (and back-volume density)  
* Clipping that is crystal deformation (up to ~30% in flawless crystolecules)
+
* Clipping - a crystal deformation is needed to open the lock <br> (unlike macroscopic gemstones up to ~30% deformation is possible in flawless crystolecules) <br> When using clipping either one accepts significant energy loss or one gives the clips a shape that is grabbable.
* Sparsely packed covalent bonds - reopenable in vacuum
+
* Sparsely packed covalent bonds - (only reopenable in [[vacuum handling|practically perfect vacuum]])
* Densely packed covalent bonds - non reopenable
+
* Densely packed covalent bonds - (not reopenable at all - see: [[atomically precise disassembly]])
 +
 
 +
Note that:
 +
* If an energy barrier of the lower levels (a bunch of covalent bonds) is overcome first it leads to a complete destruction of the structure.
 +
* Interfaces could be hierarchically locked with sliding planes. ['''todo:''' add info-sketch]
 +
['''todo:''' calculate the amount of reduction in probability of failure (in chained shape locking structures) depending on contact areas and temperatures]
 +
 
 +
== Basic serial chains using shape locking ==
  
 
Examples for possible solutions of this problem (1D structure examples):
 
Examples for possible solutions of this problem (1D structure examples):
* [http://www.thingiverse.com/thing:591203 sturdy chain that uses shape locking]
+
* [http://www.thingiverse.com/thing:591203 sturdy chain that uses shape locking - leave to thingiverse]
* [http://www.thingiverse.com/thing:200203 serial hierarchical locking structure]
+
* [http://www.thingiverse.com/thing:200203 serial hierarchical locking structure - leave to thingiverse]
  
['''todo:''' investigate amount reduction of probability of failure in chained shape locking structures]
+
The necessary surface area for energetic locking via VdW sticking may be includable in a distributed form along the whole length of the chain ['''todo:''' investigate this].
----
+
The necessary surface area for energetic locking via VdW sticking may be includable distributed along the chain [['''todo:''' investigate this]].
+
  
Note that an too long chains make parallel assembly process impossible thus chains shouldn't be made longer than necessary.
+
== Assembly forking = Disassembly merging ==
One can also merge the shape lock chain such that one ends up with a tree topology in the order of assembly.
+
That way a high surface area energetic end lock may be more naturally includable.
+
Kartesian 90° turns can be used to tie chains together.
+
E.g. to disassemble a cube shaped assembly the disassembly must start at a corner then work down an edge proceed along a surface and finally disassemble the whole volume.
+
  
One can also include forkings in the shape lock chaining.
+
Note that too long chains make a parallel assembly process impossible. Thus chains should not be made longer than necessary.
 +
To reduce that issue in structures (we are deviating from linear chains now) one can include '''forkings''' in the shape lock chaining.
 
That is at some point at least two parts need to be removed such that the held part can be removed.
 
That is at some point at least two parts need to be removed such that the held part can be removed.
Then one ends up with a directed acyclic graph topology.
+
This can increasing accessible working spots and speed up both assembly and disassembly.
----
+
The downside is that one ends up with many open ends that all need energetic locking.
*Why not use clipping? Clipping may make recuperating energy in the recycling process harder.
+
*If an energy barrier of the lower levels is overcome first it leads to a complete destruction of the structure.
+
*Interfaces could be hierarchically locked with sliding planes. [Todo: add info-sketch]
+
  
== Usage in bigger scales ==
+
== Assembly merging  = Disassembly forking ==
 +
 
 +
One can '''merge''' the shape lock chain such that one ends up with a tree converging topology in the order of assembly.
 +
That way one can resort to only one single energetic end lock.
 +
Many parallel chains of equal length that contact side by side could be tied together at their ends by turning 90° into single orthogonal chain at their ends. This would make A single 2D sheet. Many of those sheets could be tied together similarly to make a cuboid.
 +
To disassemble such a cuboid shaped assembly the process must start at a corner then work down an edge proceed along a surface and finally disassemble the whole volume. The disadvantage is that when starting the disassembly work there is only one point to work on.
 +
 
 +
== Summary ==
 +
 
 +
Inclunding both merging and forking one ends up with a directed acyclic graph topology.
 +
 
 +
At temperatures around room temperature there probably wont be so much necessity of shape locking.
 +
['''To investigate:''' How much shape locking is necessary in applications that are going to the limits of diamondoid materials]
 +
 
 +
There is a need for methods to find an optimum.
 +
The product should not resemble a challenging shape lock puzzle but something that is most practical.
 +
 
 +
= Usage in bigger scales =
  
 
To make assembly reversible with low energy turnover while retaining near full material strength
 
To make assembly reversible with low energy turnover while retaining near full material strength
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* [[Recycling]]
 
* [[Recycling]]
  
== Usage in hierarchies ==
+
= Usage in hierarchies =
  
 
...
 
...
 +
 +
 +
= Related =
 +
 +
* [[Connection method]]
 +
 +
= External links =
 +
 +
* Remotely related: Wikipedia: [https://en.wikipedia.org/wiki/Mechanically_interlocked_molecular_architectures Mechanically interlocked molecular architectures (MIMAs)]

Revision as of 11:59, 25 August 2018

This article is a stub. It needs to be expanded.

(also called: shape locking, positive locking, positive closure, ...)

Usage against thermal Van der Waals bond breakage in the low nanoscale - hirachical locking

When the contacting area of two building blocks is made smaller then they wont stick together as strong as before. If the contacting area gets so low that the Van der Waals bonding energy falls in the range of the energy range of the thermal excitations it becomes likely that connections get knocked open just by chance.

Note that the critical surface area is rather small for room temperature and bulk (hydrogen terminated) diamond. A nice thing is that with linear rising contact area breakage probability for the VdW-bond falls exponentially thus areas that will never break are quickly reached.

Shape locking might be especially important for high temperature applications where small contact areas become insufficient to hold things together.

Hierarchical locking

To prevent building blocks from falling apart by accident one can chain shape locking together. Part A can't be removed because part B is in the way. Part B can't be removed because part C is in the way. And so on and so forth.

The last clip that does not use shape locking but energetic locking must be strong enough to reliably withstand thermal fluctuations of the operation temperature. Used can be:

  • Van der Waals sticking with sufficient surface (and back-volume density)
  • Clipping - a crystal deformation is needed to open the lock
    (unlike macroscopic gemstones up to ~30% deformation is possible in flawless crystolecules)
    When using clipping either one accepts significant energy loss or one gives the clips a shape that is grabbable.
  • Sparsely packed covalent bonds - (only reopenable in practically perfect vacuum)
  • Densely packed covalent bonds - (not reopenable at all - see: atomically precise disassembly)

Note that:

  • If an energy barrier of the lower levels (a bunch of covalent bonds) is overcome first it leads to a complete destruction of the structure.
  • Interfaces could be hierarchically locked with sliding planes. [todo: add info-sketch]

[todo: calculate the amount of reduction in probability of failure (in chained shape locking structures) depending on contact areas and temperatures]

Basic serial chains using shape locking

Examples for possible solutions of this problem (1D structure examples):

The necessary surface area for energetic locking via VdW sticking may be includable in a distributed form along the whole length of the chain [todo: investigate this].

Assembly forking = Disassembly merging

Note that too long chains make a parallel assembly process impossible. Thus chains should not be made longer than necessary. To reduce that issue in structures (we are deviating from linear chains now) one can include forkings in the shape lock chaining. That is at some point at least two parts need to be removed such that the held part can be removed. This can increasing accessible working spots and speed up both assembly and disassembly. The downside is that one ends up with many open ends that all need energetic locking.

Assembly merging = Disassembly forking

One can merge the shape lock chain such that one ends up with a tree converging topology in the order of assembly. That way one can resort to only one single energetic end lock. Many parallel chains of equal length that contact side by side could be tied together at their ends by turning 90° into single orthogonal chain at their ends. This would make A single 2D sheet. Many of those sheets could be tied together similarly to make a cuboid. To disassemble such a cuboid shaped assembly the process must start at a corner then work down an edge proceed along a surface and finally disassemble the whole volume. The disadvantage is that when starting the disassembly work there is only one point to work on.

Summary

Inclunding both merging and forking one ends up with a directed acyclic graph topology.

At temperatures around room temperature there probably wont be so much necessity of shape locking. [To investigate: How much shape locking is necessary in applications that are going to the limits of diamondoid materials]

There is a need for methods to find an optimum. The product should not resemble a challenging shape lock puzzle but something that is most practical.

Usage in bigger scales

To make assembly reversible with low energy turnover while retaining near full material strength

Usage in hierarchies

...


Related

External links