Intercrystolecular snapping modes

What is considered a to be a "snap" here?
A more or less forced slow motion (nm/s to mm/s) causing
– a sudden removal of motion constraints and following
– a more or less violent fast mechanical relaxation near the speed of sound (many m/s to km/s)

The forced motion can but does not need to provide the majority for the energy for the snap
it can also just release energy that was earlier store in the system.
The forced motion must merely provide enough energy to overcome the activation energy for the snap.

(wiki-TODO: add illustrative images)

Wedge slide snapping

A crystolecule is released while suberlubrically contacting an other crystolecule.
The crystolecule will snap to the location and orientation of maximal surface contact area (surface tension analogy). Perhaps the most obscure / unexpected one of the spamming modes.
This snapping mode is related to the wedge slide force that should be very useful
for the creation of compact and tunable weak force springs.

Level of energy

• quite weak, less than bend snapping
• likely less than notch snapping in most if not all cases (for same surface area)
  => thus the need for superlubric interfaces for this snapping mode to be available

Notch snapping

A crystolecule part contacts an other one and snaps to the next notch in commensurate atomic alignment.
I.e. the atomic patterns interdigitate and there's a jump to the next notch due to a shearing force.

Notch snapping can likely be avoidable in assembly and disassembly of structures,
It seems likely that in most cases such snaps are prevented by larger back-holding forces.
In particular face-to-face sticking vdW forces towards the actuating part may prevent notch snapping.
It depends on the ratio of surface areas.

It may even be slightly challenging to intentionally provoke a notch snap.

Cases of weaker back-holding forces that notch snapping forces may be able to overcome:
– shifting a part with merely an edge or a corner of an other part (low attractive vdW forces)
– competition with higher energy notch snapping on a second contacting surfaces that is forcibly moved
– Superbubic sliding to maximize contact area (surface tension analogy)

Level of energy

• low energy snapping mode

Clap snapping

A crystolecule part snaps over from a smaller contact area to a bigger contact area.

In symmetric cases (like usually unnecessary gripper claws opening) there won't be a snap.
There will still be a one bit of entropy truly random outcome.
See page: Well merging

Level of energy

• mid energy snapping mode
• can possibly be > covalent bond energy given enough area acting

Bend snapping

A crystolecule part is bent and then suddenly released without any back-holding force.
Many covalent bonds are stretched and they can be stretched/strained to a high degree.
More than 10% (see page: Superelasticity).
Thus such snaps can release a huge amount of energy.

Bend snapping can likely be avoidable in assembly and disassembly of structures,
it may sometimes be desired, but in most cases weaker energy barriers should easily suffice
i.e. easily prevent thermally activated fall-apart.

Level of energy

• high energy snapping mode
• can easily be > covalent bond energy
• can easily be >> vdW energy >>> notch energy

Snapback

This is sort of surface localized bend snapping.
It can be just single individual covalent bonds that snap back from a bent position
See main page: Snapback

Level of energy

• depends on the number of bonds bent
• much less than bend snapping as it is located on surface only
• much more than notch snapping as the benting of covalent forces is involved, not just redirected vdW forces

Related

• Snapback
• …