If I were to do the calculations, I would always work with stress, because ultimate stress is constant from problem to problem if the same material is used. It helps to spot errors, if any.
Ultimate strength = 550 mPa.
Stress under load = 64000/(7.6*10^-4)
=84.2 mPa
Now find the factor of safety from
F=ultimate strength / stress
Note: The conversion factor from cm² to m²l is 10^-4, as explained in
http://www.jiskha.com/display.cgi?id=1372041297
What is the factor of safety of a steel hanger having an ultimate strength of 550.000MPa and supporting a load of 64000.000N.
The steel hanger in question has a cross sectional area of 7.600cm^2
ANS= Round to 3 decimal places
Safety factor = design load/ load
= 550.000MPa = 550000000Pa
= 550000000/ 64000
= 8593.75
tension design = 550MPa * 0.076M^2
= 18.000
Have I messed thing up?Please let me know if I am on the right track. Thanks.
1 answer