Is there an engineer in the house?
I’m hoping to get some input from someone who is preferably smarter than me, has an engineering background, and possibly some experience in computer-aided design.
Consider the structure of the tunica albuginea of the penis. It is generally considered to classically have 2 layers, the outer layer consisting of collagen and elastin fibers oriented primarily in a longitudinal direction, and an inner layer with fibers oriented primarily in a radial direction. Actually, I think it is a bit more complex than that. There are some individuals in which tissue analysis has revealed three layers, and some with a single layer, presumably with fibers oriented in multiple directions, or perhaps on a bias, like a Chinese finger trap.
Assuming the 2 layer, outer-longitudinal, inner-radial model, and assuming that the layers can be successfully deformed and/or remodeled independently of each other:
Lets say we do something that either physically lengthens the structure of the outer layer, or increases its compliance, or both, but has no effect on the inner layer. It seems to me in this circumstance if the intra-cavernosal pressure at erection remains the same, the erect penis will be longer than before, but probably the same diameter and circumference.
What happens if we do the opposite? If the outer layer remains unchanged in physical stretched length and compliance but the inner radial layer is either more compliant or its fibers have been physically elongated and the erection pressure remains the same, it seems clear that the penis diameter and circumference will be greater. But will the erect penis now be at least fractionally shorter since those same longitudinal fibers are now stretched around a penis of substantially more volume, sort of like the long, thin balloons that shorten as you blow them up?
It seems that someone here might be able to devise a computer model to give some input regarding this question.