Author Topic: Naming ropeParts as components in a working support structure/architecture  (Read 156 times)

KC

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Personally i think tho rope is a continuous ribbon, rope under load has separate 'ropeParts' as mechanical functions,
Just as other support against load architectures, of separate connections in other materials.
>> only rope provides own connections between these parts/functions so seamlessly, that fools the eye
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Arcs are the worker bees in this, able to use all tensions for controlling frictions and support as one.
nonArcs/linears are only extensions to/from arcs, with some of tensions, rest used alone and separately for controlling frictions ( that arcs use all tensions for). 
Arc of 360degrees or more can give grip.
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i name most Turns as compondings of 180degrees arcs, Turn as 180degrees, a Round as 360degees so adds together to be a Round Turn 540degrees etc. w/some consistency and definition away from RT as 360degrees view.
180.    name.                          abbrev.         
1x.        Turn.                            T.
2x.         Round.                        Rnd
3x.         Round Turn.               RT
4x.         Double Round.          dbl.Rnd
5x.         Dbl. Round Turn.       dbl.RT
6x.         Triple Round.             3xRnd
7x.          Coil.                            Coil
the Rounds that end opposite direction than input are not seen that much.
Inside knot internals of turns, crossings, bends etc.
i determine where endpoints for each 180degrees arc and nonArcs (linears) are by if are either in direction or counter- direction of the empowering pull ( mostly SPart) to define.
Also midpoint 90degrees of 180degrees arc creates a force of own in same direction as ends.
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The 90degrees/ 'half-arc' is a different matter, as a cross-axis lateral mechanic.
« Last Edit: November 15, 2020, 05:12:47 PM by KC »
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agent_smith

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Thank you for your post KC - all very interesting.

I am trying to extract some practical understanding from your post...

Have I got this brief synopsis correct:?
1. An 'arc' or curve within the core of a knot is key to understanding its response to load.
2. Linear (straight) segments are merely conduits to transfer force from one place to another.
3. U turn is 180 degrees, a turn is 360 degrees, a round turn is 540 degrees.... with U turns (180 degree changes) being a fundamental component of all arcs/curves?

How does core compression fit into this conceptual framework? (that is, as load is applied to a knot, its core undergoes compression).
From a practical standpoint, we know that some knots resist compression more than others - which relates to why some knots are vulnerable to jamming while others are resistant to jamming.
Rope segments crush/trap adjacent or underlying segments - which inhibit slippage but allow s-t-r-e-t-c-h.
A rope segment that overlays and crushes its neighboring segment within the core affects transmission of force through the rope segments. Distribution of force within the knot core is not uniform or linear - there can be localized stress concentrations and heat build-up.

Note: I am simply trying to understand your post and place it within a practical meaningful framework - I am not denigrating your post or trying to derail it.
I am respectfully trying to extract a simplified meaning!

Edit: Typos/grammar corrected! Got to turn auto-correct/spelling suggestions off...
« Last Edit: November 16, 2020, 10:44:27 AM by agent_smith »

KC

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At different times 360degrees has been said as Round Turn, i've always felt 540degrees was correct.
To naming general arcs that are the real magic or working ropes in their simplest forms;
i think the below picture is my best concise take on it.
>>note most top arcs shown as types of 'turns' until coil, while bottom arcs are  consistently 'rounds'
>>Also how a Turn + a Round = a Round Turn in this naming scheme

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i think tho the rope goes round and round; it presents different force patterns directionally thru from a linear input (SPart)
>>thus best nip is always on opposing side of the host from the linear DIRECTION of input load imposed
>>and then under the most intense, raw primary Turn
>>this best nip position only changes inside that primary Turn when a change of direction
Just as with a fanbelt on pulleys, the position of the most harshest, complete seating is on opposite side of the DIRECTION of pull on the host mount/pulley(s).
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KC

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3 basic knot parts in simplest Half Hitch(HH) working in arcs non/90/180:
Standing Part(SPart) forms a nonArc (linear) that imposes the load into knot
>>even tho bent is a linear with endpoints pulling opposite (vertical) directions
Feeds into a 180 Arc
>>ends of 180 Arc point in same direction
>>Being the primary Arc, points same direction as SPart pulls
Feeds into a 90 Arc
>>whose endpoints are at right angles/90 degrees to each other
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SPart input + primary turn are most rigid parts of knot, and form a hook to hold the load
>>rest of knot is keeper and ballast to the 'hook' to keep it working in place carrying load.
SPart functions as loader(of forces), arcs as reducer(of forces) followed by tailer/keepers(ballast against reduced forces)
(tailer as in sailor that keeps tension pull/reeling in after capstan as crew cranks capstan)
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As long as the linear input pull of the SPart is 'South', the best Nip will be at 'North' side of host mount, under the primary Turn.
>>the only way to change that position and where endpoints are (that define arcs etc.)is to change the DIRECTION of the linear input SPart
A radial imposed load (as in Binding) would have NO directionality, as the force is evenly diffused all around.
>>a linear imposed loading will be focused (not diffused) directionally, and this influence carries even into the subsequent arcs
This focused linear input imposed is converted to radial control, so degrades thru the rope to nip(s).
>>radial imposed loading into same arcs is not a conversion, so gives equal tensions all around to nip(s).
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The 90 Arc shears across the sole supporting column of support to the load (SPart)
>>rendering it less efficient support against the load, but is tighter on host in trade.
>>you can even crank this area sequentially tighter, this will render SPart even less efficient as grips host tighter
>>thus same load force can be used to power efficiency or tightness but not both at once in simple HH
If take advice in ABoK lesson #1669: "...Round Turn on the Standing Part adds materially to the strength of the knot."
>>The Round Turn as a contraption pulls more along SPart more like splice or Cat's Paw
>>more than shearing across the SPart support perpendicularly.
This is done under the same loading, the tradeoff is less of the loading used to tighten more on host
>>so RT around SPart is 'stronger' but grips host less in trade vs. Turn around SPart shearing across.


edit.
Dan Lehman has said finds this effect of RT around SPart to be more efficient/stronger as reduced if an RT on host mount pre-fixed the RT on SPart.
>>i think that would be because of the reduced force passed from the pre-fixing RT on host,
>>to receiving RT on SPart, and less able to grab as hard to pull along the support column against load
>>rather than across it.  So cuts more across SPart, more like HH.
So a trade off between RT on host that can spread out rope wear in small host mounts to be more enduring
>>or put RT on SPart instead to increase that durability
When working 500# and greater; in the air, w/stiff impacts on rope, right next to you; tend to tweak strength where can to best possible, quickly for scenario.  With habitual overkill on the bright side, so no overkill on the dark side!  So as days become routine, any natural complacency is mostly covered by the good habits and fought thru puzzle of architecture to control target tweaked to scenario unlike any other challenges to self.
« Last Edit: November 23, 2020, 01:38:32 PM by KC »
Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~