Lazarus wrote:Baronvonrort wrote:JohnV wrote:There is plenty of evidence to support the fact that carbon fiber was the wrong hull material for those depths . Including the fact it failed and 5 people died . The one built by a TV technician here in his back yard went to 12 000 meters and is still operating . Why ? because it's a proven design using proven materials . Five people are dead and some people are still trying to say the sub construction was fine .
Unbelievable .
What factor of safety was that metal sub designed with?
I bet is was nowhere near as low as 2.25.
Ask any engineer if they would dive down to those depths in anything with a factor of safety of 2.25 i would bet they all say no.
I would say, Baron, that the "safety factor" you quote is moot.
The proof is in the fact that the metallic sub has been down numerous times to far greater depth and it brings its crew back alive, and is still in a certifiable condition.
Unlike the Titan, which turned the crew to chum.
Sounds like a pretty good proof of safety to me.
The first question older engineers ask when something breaks is - what was the factor of safety?
With FOS of 2 you're operating at half the breaking load which is probably why that CEO didn't want to hire old white guys they know something with FOS that low has a limited life.
FOS is calculated from breaking load there is something called Youngs Modulus to consider which is where something goes through inelastic deformation before it breaks. If you load anything up and it bends/stetches then springs back to it's original shape you haven't exceeded Youngs Modulus. If it doesn't spring back you have exceeded YM.
With steel it doesn't just break before breaking load is achieved it will have inelastic deformation before failure this can happen around 70% of breaking load.
Factor of Safety is one of the first considerations with any design along with Youngs Modulus when you consider consquences of failure.
they shoulda been smarter and visited north korea instead 
