Recent content by B0B

Using an amp meter to measure current proved impractical. Using a load cell provide a direct and hopefully better measurement. I'm going to get a 20K lbs load cell. Using a snatch ring and my 12K winch, I should be able to put 20K pounds tension on a rope. The ropes tested all have a MBS of ≈...

Great info. The pulling vehicle typically slows down very quickly. I have two safety blankets and I fill the storage pockets with sand, dirt, or water bottles to add more mass. It's a pure momentum play. In most cases the mass of the rope is not that great and the blanket can prevent damage...

From the cited PDF I read that as shock loads, aka, high speed loads from a vehicle going 15 MPH yanking on a vehicle in mud is more elastic with better recovery than slow speed loads (aka, my testing approach with a winch). Am I reading that right?

If it was a spring, the 30' rope would have 2/3*K of the 20'. But it's not a spring. When I said at high V it's close to linear, I'd be measuring at a very slow speed which is the least linear.

Very useful, thanks for posting. From what I know, kinetic ropes are very similar, just bigger. That's super useful. However to a discount engineer or a retired drywall contractor where close enough counts, at high V, linear is a good approximation. The only way I could measure is with a full...

Can't I just plot deflection vs load for a fixed rope to see if it mimics a spring?

Shooting from the hip. If a spring has an elastic limit of 1 kg, 1,000 springs in series would have an elastic limit of 1,000 kg. I'm convinced that kinetic ropes act like springs and if for sure ##F_{MBS}## independent of length rules out a spring, I say it is dependent. WAUG (wild ass...

It seems very obvious now that ##F_{MBS}## is dependent on length. I'd venture to guess those numbers are for a 30' rope, which is 90% of the sales.

I never said that and I've stated many times there's no relationship to ##F_{WLL}## and stretch. ##F_{WLL}## is just ##1/3*F_{MBS}##

How is that different than with N ropes in series where each rope has 1/n the displacement?

> (which is not a constant if you get 30% stretch up to ##F_{WLL}## for ropes of different initial length) I know that part is wrong. ##F_{WLL}## is just ##F_{MBS}/3## and has nothing to do with how much the rope stretches. The only thing we know is up to 30% stretch within the elastic limit...

I'm not following. Why won't the energy stored in a rope of length L using the K for a rope of length L not be ##\frac{1}{2}kx^2## ? And I don't see how it differs for 2 springs in series, 3 springs in series, etc. Sorry, I took a year of physics 45 years ago. I haven't done any LaTeX in 30...

I think I made that clear long ago K depends on length, just like two spring in series make K 1/2. Spring rate is dependent on length as I said. Maybe I'm not understanding your question or assertion

That's not how ropes work. MBS is invariant of length. But within MBS a rope acts like a spring. Elastic stretch is invariant of radius and length. It's 30%. But kinetic ropes are only sold in 2 lengths, 30 feet (80% of sales) and 20 feet. K is a function of length. But K30 = 2/3*K20 where K30...

I think your saying, just like a spring, ##k## is dependent on length. Put two springs in series and and k prime is ##k/2## ##k## is dependent on length and radius of rope. Rope distributors sell ropes of a given radius but different lengths with the same WLL and MBS. I think MBS is...