Originally Posted by planemechanic
Not finite model analysis. What I want to know is that no airplane is certified without meeting the proper TESTING that is required. As someone who is a certified mechanic and with some engineering training I do understand what is required. No other aircraft has been ceritified without proving the wings don't break until 150% of design strength.
Airplanes are compromises. If you build it too strong it's too heavy to fly. Not strong enough and it breaks.
OTOH, what stone tablet has that magic number "150%" written on it? Sounds like an arbitrary rounded off number. From the 1930's pre computer school of engineering. "Hey boys, make it with a 50% safety factor. That ought to be enough."
Why can't 145% be safe? Perhaps one that passes 155% will be ten times less likely to ever fail than a 150% design. Is that a better number? I'd like to believe that that 150% is a carefully thought out studied value. OTOH, it is set by a government agency. . .