> I take it there's more to it then just asking the computer "hey, will this 
> break if I put 25 N through it?"

Not much more, just specify which parts are fixed (eg mounting brackets) and 
then tell it which surfaces to apply a force to.  It will then run some sort 
of iteration algorithm until it has "solved" the structure so that all 
internal forces are perfectly balanced.  Then you can just ask it for the 
maximum stress in the structure and see how big it is compared with the 
yield stress of the material...

> At what point does it become cheaper to just make the thing rather than 
> simulate it?

Hmm, the first samples are always quite expensive to make because you are 
making so few of them, but usually it's more a time thing than money.  It 
can take 2 or 3 months from finalising the design until you have assembled 
samples in your hands, and of course the customer usually has a deadline for 
releasing the product so you can't just carry on making more and more 
samples until you get it right.  If you know something is critical to get 
right and you haven't done it much before, then you simulate it.

> Mmm, ingenious.

Similar to how your steering wheel is connected to the wheels by a 
telescopic tube, so in the event of an accident the telescopic bits collapse 
rather than the rod coming through the front of the steering wheel and into 
your chest!  Although Jeremy Clarkson would say that would make people drive 
safer...

> Well yeah, it's going to depend on how safety-critical it is. If you're 
> making a coathanger, probably not much need to test it. If you're making a 
> karabina... there are probably legal requirements for exhaustive testing.

Well yes, and then you get things inbetween, like the wrist strap for the 
Wii remote control, where for some reason they didn't realise it would snap 
if you pulled it hard.  I mean WTF how can you miss that one?  I would have 
thought they would have got some really strong guy to throw it around while 
measuring the force, and then made sure it could withstand double or 
something.  Maybe Japanese "strong guys" are not that strong :-)

> One thing I always wondered... You see people doing all these crash tests, 
> right? So... where the hell do you get an endless supply of red cars to 
> crash into things?!

A car factory?  They make lots of prototypes too for many different 
purposes, btw I don't think they have to crash very many to pass the 
official tests, maybe even only 1 car, IDK.

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