posted by stacey graham on .
A large chandelier weighing 1500lbs. is suspended from the roof of a theater lobby. The steel pipe from which it hangs is 20ft long. Determine the size of the pipe necessary to carry chandelier safely. Use A36 steel. What is the resulting elongation of the pipe?
I calculated reqd A=54.3in^2 to get diameter of 8.31in and elongation of 216inches. Am I doing it right?
I believe you are way off. Your tensile stress would be only 27 psi and the elongation 90% with you numbers.
Too little stress; too much strain.
The yield strength of A36 steel is 36,000 psi. Your stress is over 1000 times less than that.
You must know what the formulas are for stress and strain. You must be using wrong units or making a large computation error.
Do they specify a factor of safety? You will need one. Four might ne reasonable