War in space

> Actually there's also longitudinal stress, 50% of the
circumferental
> stress, which is caused by air pressure on the end caps.

How does it come out so simple? It seems as though it has to be
something more complicated, because the circumferential stress
depends on the g's whereas the longitudinal stress depends only on
the pressure.

> Well, you've reduced the load on the structure by more than the
size
> of the hole.

I still don't get it. How do those quantities even have the same
dimensions?

--- In spacesettlers@yahoogroups.com, Ian Woollard
wrote:
>
> On 1/10/06, Dan Wylie-Sears wrote:
> > > You've just reduced the main load- atmospheric loading at the
> > > breach point, so it might well survive in fact.
> >
> > The load on a sphere or cylinder is from the whole rest of the
> > structure.
>
> True, but you have a safety factor of maybe 2-4 on the whole
> structure, so punching a few smallish holes in the cylinder makes
> little difference.
>
> > It's simpler to visualize for a cylinder: the stress is
> > pure tension, all in the circumference direction,
>
> Actually there's also longitudinal stress, 50% of the
circumferental
> stress, which is caused by air pressure on the end caps.
>
> > and two strips
> > along opposite sides have to keep the two halves from going their
> > separate ways: they have to bear the component parallel to their
> > tangential direction, of centrifugal weight plus atmospheric
> > pressure of the two halves. The outward force acting at that
point
> > is perpendicular: varying the amount of mass or air pressure
there
> > has no effect on the tension there, and maximal effect on the
> > tension 90 degrees away.
>
> Well, you've reduced the load on the structure by more than the
size
> of the hole.
>
> I guess punching a hole in the wall has a stress concentrating
effect
> around it; I vaguely recall it's about a factor of 3 for a circular
> hole. It's somewhat higher for a crack.
>
> > >speed cameras that increase the death rate<
> >
> > How does that work?
>
> Death rate goes up when they install cameras. Probably everyone
> stomping on their brakes on straight roads and getting rammed from
> behind and stuff.
>
> --
> -Ian Woollard
>
> Identity cards, cameras on every corner, long term detention
without
> trial, electronic tapping and reading of email/phone calls, speed
> cameras that increase the death rate, extradition for torture -
It's
> all double plus good, Big Brother Blair and Uncle Bush are my
friend!