Physics of V-Stretches

Mcnitro,

:D sounds like quite a problem just in terms of vocabulary and my German is worse than my physics so I won’t suggest posting the German version.

The properties of the tissues is of course not simple and probably not even consistent between different people (maybe consistent enough). I’ve found a lot of information on the elastic/plastic properties of metals but none on penises I guess you could lead the field here.

Trigger,

Like you I start from the position that V-stretches work, the question is how. I think my understanding has improved during the course of this thread but I don’t think we are near a solution yet.

Here’s my best effort at understanding it so far, hopefully in straightforward English.

If we go back to the picture in mcnitro’s pdf it shows basically a U shaped penis with a fulcrum point pressing down in the middle to form the U. Nedd already detailed how a vector is used to calulate tension.

If you take the inner side of the curve of the penis at any point around the fulcrum and draw a tangent out from the fulcrum circle (straight line out from the curve, equal angle on both sides) you can get a direction for a vector and can calculate a tension. If you do the same on the outer edge in the same place on the fulcrum you’d get the same vector and the same tension.

What this is saying is that the tension on the inside of the penis is the same as on the outside. What we are not taking into account though is any tension inherent in the penis simply due to the fact that it is curved. We know from plumped bends that bendind the erect penis causes tension on the outside of the curve and less on the inside of the curve. Thats erect though, with a flaccid penis the inside of the curve will be a lot closer to the outside of the curve but there will still be a tension gradient in any penis cross section around the fulcrum, a larger tension on the outside of the curve.

This is just a complicated way of saying the outside of the curve has to travel a longer length than the inside of the curve and so the outside has to stretch more. So if we are feeling greater tension at the fulcrum it might be because the tension is focused on the outer side of the curve and the tension is less on the inner side of the curve.

The difference in length travelled probably doesn’t have to be that great to have an effect and it won’t be the great.

This seems to make sense but in practise if I do an inverted V-stretch I feel a definate increase in tension on the underside of the penis beyond the fulcrum point. That could be due to the way the penis is deformed over the fulcrum simply being like chenging the direction of the stretch and/or departure points from the fulcrum for the top and the bottom of the penis. I’m a bit fuzzy here.

Beyond the focusing of tension to a particular side of the penis there is also the matter of mechanical advantage. Again When I was doing inverted V-stretches over cans I found that I could find a good position to stretch straight armed leveraging my entire shoulder into the stretch.

I doubt this is anywhere near the whole story.

>This seems to make sense but in practise if I do an inverted V-stretch I feel a definate increase in tension on the underside of the penis beyond the fulcrum point. That could be due to the way the penis is deformed over the fulcrum simply being like chenging the direction of the stretch and/or departure points from the fulcrum for the top and the bottom of the penis. I’m a bit fuzzy here.

It seems counterintuitive that the inside of the curve gets worked the most during a V or A-stretch. I speculated about why that happens here. It’s only a theory; I may be wrong.

That makes a lot of sense. Strangely I always got that feeling even when using the edge of a chair as a fulcrum or at least I think I did. In that case the fulcrom point was lower than the underneath of the penis which should invert your triangle.

Does anyone reading this do a v-stretch over the edge of a chair? Where do you feel the stress?

I’ll have to test that out.

The physics is simple. MagnumXL’s theory that tension was magnified throughout the penis solely by adding a fulcrum is patently incorrect. It’s easy to see why, and it’s easy to see exactly what mistake he made. This point should not be in dispute. You’ll find the only person trying is someone who doesn’t even understand vector math I learned when I was 14, but still for some unfathomable reason thinks he belongs in this discussion.

But, as I said in my very first post, different areas may be emphasized in different ways.

Yes, I’ve tried them (V and A stretches as opposed to coke can type stretches), and frankly I don’t feel any difference whatsoever. The stretch may increase with accompanying increased pulling power, but only by the amount it would increase if I pulled harder without the fulcrum.

They’re pulling harder. Or like I said, different areas emphasized at the expense of others. Doing a stretch over a coke can for example may cause the septum to take on more of the tension, as it is effectively traversing an arc of the same degree but greater radius, i.e. a longer distance than the distance the area of the penis in contact with the coke can traverses. More strain = more stress = more tension. The overall tension of course doesn’t increase; the septum takes more tension at the expense of the other parts. And, this is just a possible example, I don’t know whether it actually happens.

Isn’t that a tension gradient?

If someone’s grip only allows a certain force to be exherted, then emphasizing different areas individually might allow for a better overall workout, analagous to muscle isolation in weight training.

Ned geez take a chill pill. Do you always have to be the only person who could possibly be right?

Even if you are right about what your saying memento is right about what he is saying. Havn’t you ever heard of different perspectives? You could really keep your temper from getting the best of you if you would try a different perspective yourself.

Just because you think everyone should see you as an expert dosn’t mean they will.

What shows up most is you not being in controlof your temper. But why are your panties in a knott anyway? Its a disscussion. Adults can have these and learn from them. They can be great tools to knowlge. Everyones imput is important.

Your supposed to be discussing tension not acting it out
So how about going to your corners and come out smiling

That’s the point, since a few posts memento just isn't trying to dispute the fact that the overall tension is not magnified.
Hmmm….I’d say….re-read your thread! :D

This is what we are talking about now and it means that tension changes locally. Tension than is a function of the space (constant force).

So why are you saying that there is no tension gradient?

LOL. I can’t believe I’m wasting my time with such blatant imbeciles. I’m gone from this thread.

For anyone with a glimmer of intelligence reading this thread, read my posts to understand what’s going on, and ignore everyone else.

Temper Temper

I think that it would be a tragedy to let this thread die due to the arrogant behavior of people calling themselves “A+” experts. So, if you are bored to tears reading this, have a nice day but if you are willing to understand what v-stretches are all about, please participate.

Nedd,

Since I’m really interested in your understanding of the tension gradient, it would be great if you would answer my last question.

memento,

It’s usually a bad idea to tell people what other people think, sorry for that. To say it clear, I thought you accepted the fact that the overall tension is not magnified according to the simple model I used in my .pdf and that, according to the real situation (the penis with its diameter and properties of the tissue) the tension could be magnified, right? Please correct me, if I’m wrong.

So here’s what I think ( without the tensor analysis :D ):

If we take the simple model I used in my .pdf, it becomes clear, that the tension is not magnified, by adding a fulcrum. If we take a look at the penis the situation might change. I don’t think that we are allowed to transfer the results to real life.

Just think about the following experiment:

1. Take a white elastic rope, that is easy to stretch. It simulates the penis.
2. Take a black edding and draw two lines on opposite sides of the rope.
3. Take a knife and carve small cuts into the black lines vertical to the rope.
4. When you stretch the rope now you can see the small white gaps growing in the black lines.
5. When the rope is curved with on black line on the outer and one on the inner side of the curve, we see that the size of the gaps on the outer side of the rope increases while on the inner side the cuts in the black lines are pushed together. And this even without stretching the rope!!!
6. If we stretch the curved rope (i.e. over our wrist), that is covered with oil to minimize the effects of friction, we see that gaps on the outer side of the rope grow faster than gaps on the inner side. (Well here you have to look through your wrist to see the inner line ;) , so just take an empty bottle)

What did we learn? -> next post

Results:

The experiment clearly shows that we emphasize different areas in a different way by adding a fulcrum.

Let’s just concentrate on the curved un-stretched rope:

If the curve does not create an added overall tension, that would mean that the compression (negative Tension) on the inner side has to compensate the stretch of the outer side, so that the overall created tension is zero, i.e.

Tension on the outer side of the rope = - Tension on the inner side.

This would mean that the Tension (stretch on the outer side) and the negative Tension (compression on the inner side) have to increase about the same values when we travel from the middle of the rope to the outer and inner side.

This is the decisive question.

Is the curve creating an overall tension ( Stretch(Tension) > Compression(-Tension))?

If not, tension is not magnified by adding a fulcrum.
If yes, tension is magnified.

(Anyone here willing to test this with piezo-electrical materials?) :D

About the tension gradient:

In my opinion it exists. The tension changes locally by adding a fulcrum, with or without magnified overall tension. The tension in the tissue can be described as a scalar field (you have a value for each point), and it does not change chaotically. If you look at the white gaps in the above experiment you see how their size increases as you’re coming near the fulcrum point viewing on the outer side of the curved rope. You would be able to cut the penis into very small slices in with the values for the tension are the same. The gradient is a vector that shows how a function changes it’s values in certain directions of its arguments (our arguments here are coordinates of the space while keeping a constant force). The tension gradient starts on one of our virtual slices and points in the direction in witch the tension values are increasing the most.

I will post a plot of the function that describes the tension when I got the time.

Any ideas so far? ….,Nedd?

Thanks for your time,
mcn

Mcnitro,

Thanks very informative posts.

>Please correct me, if I’m wrong

Nope you are not wrong. I started off by getting my sums wrong and confusing myself but then I realised where I was wrong and said so (on page 2). As I’ve said before on this thread I’m a little fuzzy in certain areas and so I’ll ask questions until I understand. Unfortunately when having a conversation of this kind you need to be talking to someone willing to discuss where the breakpoints are.

Your rope analogy makes sense, its what I was trying to say earlier (but a lot clearer).

If you take into account what Hobby was saying about the bit prior to the fulcrum (the triangular shape) then following your model you might expect that the elastic rope would need to be attached in such a way to provide greater stretch to the bottom leading up to the fulcrum point, ie at an angle to the direction the rope travels toward the fulcrum.

The thing with the elastic rope is to be kind of accurate it would have to allow transverse compression around the fulcrum point. This isn’t a problem though because for the top top travel the same distance as the bottom the rop would have to flatten completely and even then you’d be creating a kind of oval shape to the rope stressing the sides (as seen from below the fulcrum point in a standard V-stretch).

Even if you consider the elastic rope to consist of 10 paralell strands with little friction between them the outer strands would stretch more around the fulcrum with your example.

Using the 10 strand no friction example though and adding in Hobby’s point about the bottom stretching more before the fulcrum point it seems possible that at exactly the wrong fulcrum height and diameter you might end up evening out the tenision top and bottom.

What this does tell us though is that the more we can exagerate the depth of the penis around the fulcrum the more the outer side should stretch.

Do you think its actually possible to magnify the overall tension? I guess there is friction between the skin and the fulcrum point but there is little friction between the lower skin and the inner penis. Beyond friction on the skin what is there to create extra overall tension?

[fuzzy]
If we assume conservation of energy could extra tension be created by the fact that the outer tension is greater but that the cross sectional area of this increased tension is less than the depth of the penis around the fulcrum and therefore with greater tension and less area to exert this tension across could the penis be storing more force of the force in elastic deformation?

Can one store more energy in elastic of a smaller diameter? I don’t think that makes sense.

Is this why you mention piezo as it converts pressure into electricity? What alternative forms of storage do we have available?
[/fuzzy]

memento,

unfortunately I will have to read your post several times because my English is not good enough, sorry.

…but imagine that:

If the above is true and my thumb or wrist or whatever provides a constant fulcrum so that the way the inner side has to travel has a constant length, then more girth will make the outer side travel even more way…

Then more girth would lead to a more effective v-stretch, right? :D

Ok, we’d have to stretch even harder…

>unfortunately I will have to read your post several times because my English is not good enough, sorry.
Yeah well, my English is probably a little over dense on this, in an effort to be explicit I’m probably using 20 words where 10 would do.

>Then more girth would lead to a more effective v-stretch, right?
:) What I’m getting at is by deforming the girth of the penis we have around the fulcrum making it higher above the fulcrum point we’d get more tension on the outer side.

In that case the best kind of device to create a fulcrum would be a pulley with sides and a groove thinner than the penis.

To be clear, you can have all the tension gradients you want laterally. We were talking about longtiudinal gradients, of which there are none.