Physics of V-Stretches

Hey trigger,

Not sure if this would work, but another experiment idea is to link a bunch of (identical) rubber bands together using paper clips. Connect both ends to something, such as pegs sticking out of a wall, so the ends are level. Then place a cylindrical can on the middle of the “chain.” The can should be heavy enough to bow it down. Now measure the lengths of the rubber bands along the whole chain and see how much and where they vary.

Or you could do the same with Theraband. Make marks at even intervals while it is unstretched, then “v-stretch” it and measure the distances between all the marks.

I got a thin rubber tube attached my a 2kg weight to it and placed it over a fixed fulcrum point with a similar diameter to a can of beer. It was fixed at one end to simulate the body. When i pressed down in the centre to simulate the V stretch it DID increase in length.

The problem with comparing it to physics problem from textbooks is that it is not the usual “inextensible taut cord over a smooth frictonless pulley”.

So physicists, what happens when there is a deformable elastic cord over a pulley with friction forces in effect.

Thats a good question trigger.

Nedd’s workings are based on equilibrium in a cord, what we are actually doing is hopefuly extending beyond the elasticity of the penis to the point of plastic deformation which I supposed is the equivalent of the cord fraying just before it goes ping.

Maybe he can enlighten us.

The cord deforms slightly. The acceleration is negligible though, so the tension is still as I have described. The cord fraying just before it goes ping holds the same tension until the moment it snaps, but the stress distribution and magnitude would change.

Plastic deformation could mean certain blood vessels or whatever break, causing the tension to be taken up by other things. But the overall tension still remains the same.

Friction at the fulcrum may result in less tension between the fulcrum and the base than between the fulcrum and your hand. But considering the way internal penis slides over skin, I doubt it would have any effect.

>The cord fraying just before it goes ping holds the same tension until the moment it snaps, but the stress distribution and magnitude would change. <
Thats working on a cord with no effective diameter. If a real piece of rope frayed you’d be working on less effective diameter and as you’ve already agreed that doubling the diameter is how the tension stays the same in a v-stretch, I don’t see how you can argue that reducing the diameter would not increase the tension.

>Plastic deformation could mean certain blood vessels or whatever break, causing the tension to be taken up by other things. But the overall tension still remains the same. <
We are looking for small tears here of course, meaning there will be less strength to the penis and therefore the effect of the force will become greater because there is less strength to support it.

I’m still trying to figure out why x sinned
and what exactly did he do? lol

Seriously, I’m not exactly sure what all the number crunching
is about, but would I be right in assuming your trying to figure out if a fulcrum increases load>?

I thought a fulcrum can carry load, even transfer a load to a
different point, not sure what your trying to figure out.

Also, what is plastic deformation?

One last question, with all due respect, are you guys like the resident forum scientists or something?

>would I be right in assuming your trying to figure out if a fulcrum increases load
That seems to be the subject of this thread occassionaly.

>I thought a fulcrum can carry load, even transfer a load to a different point, not sure what your trying to figure out.<
Whether using the fulcrum can increase load and under what circumstances.

>Also, what is plastic deformation?
Elastic deformation is where something extends under load and then goes back to the same shape are the load is released, plastic deformation is where the deformation exists after the load has been removed. Normally you’ll hit a bit of elastic deformation before you get to plastic deformation.

>One last question, with all due respect, are you guys like the resident forum scientists or something?
That’ll be Nedd and Tantrex.

Thank you Memento, now I know to whom to turn if I have a scientific type question, you seem to know your way around a lab yourself.

I know how to set fire to one.

No, it’s working on any cord.

What? Doubling the diameter is not how the tension stays the same in a v-stretch. I said if there were a 180 degree fulcrum, and you imagined the folded over penis was one unfolded object, with the two 10N forces pulling down and the one fulcrum force of 20N pulling up, then the stress will be the same as in the normal analysis, because the tension is doubled to 20N, but the cross sectional area is doubled too.

If you’re pulling both ends of a string with 10N then the tension is 10N. Half the cord snaps (frays). You do not change how hard you’re pulling; the tension remains identical. What changes is the cross sectional area, and hence the stress in the remaining half of the cord. The cross sectional area halves, the tension remains the same, therefore the stress doubles.

The tension in any section of penis is the same. If part of the load bearing structure in said section fails, that load needs to be taken up by some other (part of a) structure in that section. If it didn’t, the penis would split apart. That could mean each individual remaining blood vessel (ligament component, whatever) supports more of the tension than before, yeah.

I want to know exactly if and why it does increase stretching. If we know exactly why it does, we may be able to develop an even more efficient method of stretching. V-stretches do FEEL like they cause more stretching.

trigger,

Thats exactly what interests me.

>What? Doubling the diameter is not how the tension stays the same in a v-stretch. I said if there were a 180 degree fulcrum, and you imagined the folded over penis was one unfolded object, with the two 10N forces pulling down and the one fulcrum force of 20N pulling up, then the stress will be the same as in the normal analysis, because the tension is doubled to 20N, but the cross sectional area is doubled too.<

Exactly there are 2 cords. So imagine the penis as 10 cords, sharing the tension, then break one cord under stress what happens to the tension in the remaining cords.

I discovered this thread late. My two cents worth:

There is no fulcrum or leverage involved in PE. V-stretches add effect for the same reason BTC hanging does: shearing.

The penis is not plastic nor is it a cord or a collection of cables. We don’t nail our butts to one thing and the end of our penis to another to test the “fixed space point” physics described originally by “7-Up” long ago at another site.

Shearing is applying force to a material off the axis of its greatest resistance to stress in a confined span. You tear a piece of paper at a perpendicular axis to its resistance and “pinch” it so you are not fighting the span of the whole sheet.

“Shearing” is a scary word when applied to one’s penis and appropriately so. Erect bends,”fulcrum” hanging, V-stretches all increase the application of any given longitudinal force to one’s penis by the action of shearing. In terms of danger, it would therefore be a bad idea to hang erect (see Bib’s site warnings) Assuming it were possible, the greatest sin against PE safety would be erect fulcrum hanging. (see also Bib’s “two force”discussion in prior threads).

“Shearing” is a good word when applied to the concept that most of us have glans or otherwise distal portions of our penis that will not accept as much compressive force as it takes to support the application of longitudinal force of such power as to actually stretch the ligs or tunica. Here, shearing is our friend. It allows force that is insufficient to stretch tunica or ligs “on axis” to do so “off axis.” The same force is applied to a smaller area of tissue in penis shearing.

A difference between BTC ( or in lesser proportion all angled hanging) shearing and “fulcrum” shearing is the location of the increased effect. In BTC shearing the focus of the force is the more dorsal portion of the suspensory ligament (nearer to belly button, farther from balls). If you were to view the angle as a curve in a hypothetically cylindrical penis, the force is going to the “outside” of the curve. But with a “mid span” fulcrum (or V-stretching), same visualization, the force is going to the “inside” of the curve—the one where the object is in contact with the penis.

This last visualization helps explain the difference between shearing and leveraging the penis. If it were leverage, the “outside” of the curve (the side of the penis the “fulcrum” is not touching) that would get the extra effect. And it would get some extra effect—if the penis was a semi-rigid cord or cable. Because it is not, the extra effect is found at the contact point and is, therefore, shearing.

If anyone actually liked reading this and was really smart, he would say at this point,” Ah-ha! So erect bends DO involve leverage since the force stretches the ‘outside of the curve.’ Moses is a self-contradicting idiot!”

I am an idiot for totally different reasons. Here, it is my opinion that the leverage involved in erect bending is negligible compared to the shearing. The “fulcrum” of the erect bend “lever” is the compressive axial resistance of the opposing CC. That’s not a lot. However, the phenomena of fully expanding one’s CC and then applying pressure perpendicular to its axis is enough shearing force to literally break your penis with your own hands.

Bottom line: “fulcrum hanging” and V-stretches do effect increased stress, but not for the reasons that some have hypothesized.

That’s it and it is longer than I thought it would be. I apologize in advance to the Academy if anything I have stated is stupid or presumptuous. In aid of any ad hominem insults that may arise, I formally disclose that I have no scientific background and am terrible at math .

Nedd,

This was why I always used a fulcrum, to emphasize different areas in different ways - and I could certain feel the difference as the fulcrum changed. I also suspect that by using fulcrums you can alter the direction of tension. In other words, imagine your right hand pulling straight up. That line of force is going through the length of the penis. Now, your left hand is pulling laterally from the center of the shaft - while maintaining your upward pull with the right hand. So, your penis is simultaneously being exposed to vertical and lateral stresses.

But, I do want to add that I believe that a fulcrum can magnify force, on the basis of leverage. For example, imagine an olympic barbell loaded with 400 lbs. If the bar is resting on an olympic bench (with very wide uprights), you’ll see no bending of the bar. But if that same 400-lb bar were racked on a standard bench (with narrow uprights), you’d see a noticeable bend to the bar. In that sense, I believe that applying downward pressure to the center of your stretched unit puts more stress on the penis than if you were applying that pressure to the very base or to just below your glans (the 2 contact points).

However, I’d agree with you that if you’re applying 10 lbs on a center fulcrum, or 10 lbs simply hanging BTC, your ligaments are still feeling just 10 lbs of force - either way. It’s just the way the penis is reacting to those vary types of stresses which makes the fulcrum “different.”

Moses - I’m not sure where you got all that if you’re terrible at math and have no scientific background. It’s my understanding though that the flaccid penis is flexible, so cannot support significant shear forces. The erect penis wold be a different matter entirely.

That’s fine.

Only inasmuch as vertical and horizontal are components of the longitudinal tension in the penis. Your analysis is too simplistic; a horizontal force plus a couple of vertical forces does not equal “lateral stress”.

…. Your example describes a beam, not a cable, and there aren’t even any longitudinal forces involved! Cables do not support bending moment.