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Unformatted text preview: range of 135 MNm-2 . It is desired to extend the part life by another 2 . 5 × 10 8 cycles by reducing the performance requirements (and thus the stress). Find the decrease in stress range necessary to achieve the additional life using Miner’s cumulative-damage law. 3. In a more careful analysis, it has been noticed that a mean stress of about 10 MNm-2 is sustained by the part described in the previous question, under service conditions. How much would this aﬀect your ﬁnal answer? (Hint: Repeat the calculation by taking into account a mean stress of 10 MNm-2 ) (Note: σ TS = 395MNm-2 )....
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- Fall '09
- Mechanical Engineering