Tie rod performance index with safety factor and cost

[fowler2k]

A tie rod of max strength and minimum mass performance index

Max strength - τ= 2T/πr³

Min mass- P=t^(2/3)/p

I have been asked to explain how the performance index is affected by

(i) safety factor
(ii) changing the objective to minimum cost

Any help would be greatly appreciated

Thanks

 

[Astronuc]

Safety factor on what? Stress? A key dimension?

How does one define stress, and how does it relate to the dimensions.

Then think what one does to minimize stress.


To minimize cost, one minimizes material usage, e.g., with thinner load bearing sections.