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A new mathematical model predicts a knot's stability
Phys .Org ^ | 3 Jan 2020 | Jennifer Chu

Posted on 01/03/2020 8:07:28 AM PST by DUMBGRUNT

But what exactly makes one knot more stable than another has not been well-understood, until now.

MIT mathematicians and engineers have developed a mathematical model that predicts how stable a knot is, based on several key properties, including the number of crossings involved and the direction in which the rope segments twist as the knot is pulled tight.

With confidence in their model, Patil then simulated more complicated knots, taking note of which knots experienced more pressure and were therefore stronger than other knots. Once they categorized knots based on their relative strength, Patil and Dunkel looked for an explanation for why certain knots were stronger than others. To do this, they drew up simple diagrams for the well-known granny, reef, thief, and grief knots, along with more complicated ones, such as the carrick, zeppelin, and Alpine butterfly.

(Excerpt) Read more at phys.org ...

TOPICS: Chit/Chat; Miscellaneous
KEYWORDS: alexanderthegreat; boyscouts; godsgravesglyphs; gordionknot; knots
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A friend of my career Navy father, a former Japanese POW taught me the knot that was used on him.

I have had much fun with it over the years and NEVER had any escape.

Once as a student, I used the pull cord from a window shade. The subject panicked and pulled the shade down!

Starting with palms and elbows together, they can only chew through the rope.

Wrists crossed behind the back; there is NO ESCAPE!

1 posted on 01/03/2020 8:07:28 AM PST by DUMBGRUNT

To: DUMBGRUNT

Just use Alexander the Great’s method for solving Gordian knots!

2 posted on 01/03/2020 8:09:16 AM PST by glorgau

To: DUMBGRUNT

Very cool science! Thanks for posting.

What was the knot?

3 posted on 01/03/2020 8:25:59 AM PST by MV=PY (The Magic Question: Who's paying for it?)

To: glorgau

” Listen, strange women lyin’ in ponds distributin’
swords is no basis for a system of government! Supreme executive power
derives from a mandate from the masses, not from some farcical aquatic
ceremony!”

4 posted on 01/03/2020 8:26:20 AM PST by DUMBGRUNT

To: DUMBGRUNT

Are you referring to the bowline? Any Boatswain’s Mate knows how good a knot it is.

5 posted on 01/03/2020 8:29:41 AM PST by sasportas

To: MV=PY

What was the knot?
Be careful with this one.

When used on friends, use something soft and about 3/8” diameter so it does not cut.

For others, a long shoelace works well, back it up with a couple of half hitches.

Have a stout bandage shears ready.

https://en.m.wikipedia.org/wiki/Constrictor_knot

6 posted on 01/03/2020 8:32:35 AM PST by DUMBGRUNT

To: DUMBGRUNT

You can’t come out of a good square knot. That is all you need to know.

7 posted on 01/03/2020 8:34:30 AM PST by cornfedcowboy

To: DUMBGRUNT

MIT mathematicians and engineers have developed a mathematical model that predicts how stable a knot is, based on several key properties, including the number of crossings involved and the direction in which the rope segments twist as the knot is pulled tight.

Sailors and farmers have known this stuff for centuries.

8 posted on 01/03/2020 8:35:34 AM PST by PeterPrinciple (Thinking Caps are no longer being issued but there must be a warehouse full of them somewhere.)

To: DUMBGRUNT

Sailors and boy scouts didn’t need equations to tell them what they knew.

9 posted on 01/03/2020 8:37:20 AM PST by I want the USA back (If free speech is taken away, dumb and silent we are led, like sheep to the slaughter: G Washington)

To: sasportas

the bowline?

I’m very familiar with the bowline.

Until that evil car ran me and my bicycle over a few years back, I could tie one around my waist while hanging with the other hand.
I can still do the one-handed part but not the hanging part.

Not a bowline, see #6.

10 posted on 01/03/2020 8:38:51 AM PST by DUMBGRUNT

To: cornfedcowboy

You can’t come out of a good square knot.

Having lived in the Great State of Texas for some time, I knew cowboys and goat ropers.

Many had a wide knowledge of knot tying, but they always were amazed by this one.

A square knot on the right cord will hold ok but getting it snug and keeping it tight, not so much.

The thin wiry ones and females are often very good at getting out.
But not with this one.

See #6.

11 posted on 01/03/2020 8:48:37 AM PST by DUMBGRUNT

To: DUMBGRUNT

Beat me to it. Patel should have been tied up and tossed in a trunk. That’s the best way to do his testing.

12 posted on 01/03/2020 8:50:07 AM PST by bgill

To: PeterPrinciple
"Sailors and farmers have known this stuff for centuries." So have surgeons and fly fishermen!😎
13 posted on 01/03/2020 8:54:26 AM PST by Bonemaker (invictus maneo)

To: DUMBGRUNT
Ahh..."...In mathematical knot theory, you throw everything out that's related to mechanics," Dunkel says. "You don't care about whether you have a stiff versus soft fiber—it's the same knot from a mathematician's point of view...."

All well and good in the ivory tower kingdom...except that everyone who's handle ropes, cords or lines knows that material type and mechanics play very important roles in practical usage. As an example, a simple slip knot tied with a hemp rope will retain it's shape and function whereas a polypropylene, stiff and slick, will not, due to difference in amount of friction. Soak the hemp rope, tighten the slip knot and it becomes more difficult to move, plus or minus depending on need.

14 posted on 01/03/2020 9:01:11 AM PST by Covenantor (https://www. are ruled...by liars who refuse them news, and by fools who cannot govern. " Chesterton)

To: DUMBGRUNT

MIT held off on publishing this discovery until after Odumbo was out of orifice.

15 posted on 01/03/2020 9:05:57 AM PST by SgtHooper (If you remember the 60's, YOU WEREN'T THERE!)

To: DUMBGRUNT

Thanks! I was familiar with it. Nasty thing.

I’m always looking for knots that will hold reliably and untie easily (boating).

16 posted on 01/03/2020 9:11:17 AM PST by MV=PY (The Magic Question: Who's paying for it?)

To: Covenantor
Knots are some intersting things, many years of climbing and many of my fellow climbers deep into knots... I retained a few fun bits.

No knot is stronger than the rope. (NOT SOME HATCHET KNOT)
Splices can be stronger than the rope.

Most knots weaken the rope, sometimes over 50%.

Most knots have been known for a long time.
IIRC about 300? Not included the now computer-generated knots. The computers took the fun out of it for some and gave it to others.

17 posted on 01/03/2020 9:17:48 AM PST by DUMBGRUNT

To: sasportas

Nothing beats an Arkansas Knife Knot.

18 posted on 01/03/2020 9:24:47 AM PST by gundog ( Hail to the Chief, bitches!)

To: DUMBGRUNT

Here’s the gCaptain link to his writeup of the article:

https://gcaptain.com/mit-knot-study-science/

19 posted on 01/03/2020 9:25:26 AM PST by fishtank (The denial of original sin is the root of liberalism.)

To: gundog

20 posted on 01/03/2020 9:29:01 AM PST by Magnum44 (My comprehensive terrorism plan: Hunt them down and kill them.)