Posted by: Skewhole ® 11/14/2007, 18:29:45 Author Profile eMail author Edit

Hi Folks, How we can determine the factor of safety of a certain design? Is there any ref. book or standard you can share? Thanks! Winp

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Posted by: randykimball ® 11/15/2007, 23:29:54 Author Profile eMail author Edit

I generally like to design shafts to be twice to three times the required strength. Then we need to check to see that they will last enough cycles of stress flex to not break well past the intended lifetime. Most aircraft are tripple redundant. A wing to break at three times the expected load, critical flight electronics in tripple.... Lift devices I have worked on in the past were certified by testing to twice the actual load with physical testing equipment after being designed to handle tripple the load at full expected shock accelaration. Does this help? The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Thu, Nov 15, 2007, 23:32:10

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Posted by: Skewhole ® 11/15/2007, 18:11:02 Author Profile eMail author Edit

Thanks! I am new in this 'design' world, forgive my vague and unclear questions. Thanks again.

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Posted by: srtools1980y ® 11/15/2007, 01:21:30 Author Profile eMail author Edit

your question is vague.factor of safety is based on various inputs such as design,m.o.c.,manu.process,intended use,service conditions such as ambient temp.,service atmosphere. for eg.parachutes are designed for higher service factor when compared to automobile gearboxes. all lifting mechanisms using wire ropes are designed with higher ser.factor when compered to conveyors. this is not a single book subject.this is a case to case subject. rockets carrying payloads such as satelites are designed for a lower fos when compared to those carrying human payload. a sports car gearbox has higher fos than that of a passenger car.

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