2 lecture 4 - Failure Predictors and Safety Factors - slide

E successful designs mostly used as a divisor to

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview:  1 + µ Ⱥ σ 1 − σ 2 + σ 2 − σ 3 + σ 3 − σ 1 = E Ⱥ 2 Ⱥ ( )( )( ) 2 Ⱥ Ⱥ Ⱥ Ⱥ 2 2 Ⱥ Sy − 0 + 0 − 0 + 0 − Sy 1 + µ Ⱥ = 3E Ⱥ 2 Ⱥ ( = 1+ µ Sy 3E () € € σ vM = )( (σ 1 −σ2 2 )( ) 2 Ⱥ Ⱥ Ⱥ Ⱥ 2 ) + (σ 2 )( + σ 3 − σ1 2 −σ3 2 ) 2 = Sy Fd Mechanical Design Factors of Safety Design Factor of Safety, Fd Fd is of critical importance when dealing with design uncertainty systematically Features of Fd • a number greater than ONE for conservative (i.e. successful) designs • mostly used as a divisor to reduce the assumed strength of a component For example: σ(allowable) = Sy / Fd • a product of several factors (for novice designers!!!) : • a factor reflecting the consequence of failure; • factors for uncertainty due to load • factors for uncertainty due to material Mechanical Design Factors of Safety Evaluation of Fd can be: “implicit” – based on experience, sometimes dictated by standards “explicit” – determined by a syste...
View Full Document

Ask a homework question - tutors are online