This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: 2 e 2 e 2 e Total Operating Cost Total Operating Cost C = C 1 + C 2 = C m AL ρ + C e I 2 [ ρ e L/A]t Differentiating cost with respect to area and setting the derivative equal to zero gives the optimum value for cross sectional area for the minimization of total operating cost: A opt = [C e ρ e I 2 t/(C m ρ )] 1/2 Substituting A opt back into the total cost equation gives the objective function : e 2 1/2 m e 1/2 “Cost is minimized by selecting the material with the greatest value of”: M 1 = 1/[C m ρ e ρ ] “Strength is important when a busbar of large span is unsupported or is exposed to other loads . Then we require a minimum value for the elastic limit.” graphite • For cost and strength, bronzes are best • Without strength, would have selected graphite...
View
Full Document
 Spring '11
 Mecholsky
 Heat, temperature rise

Click to edit the document details