Fatigue Life Design of Mechanical Structure答案2023秋

第三章测试

1. Which is not the characteristic of real fatigue Limit （ ）
A:Fully reversed uniaxial fatigue test B:Standard, highly polished, unnotched specimen C:Group method D:Testing frequency is larger than 100 Hz
答案:D
2. The characteristics of General S-N behavior are as follows （ ）
A:S-N curves are usually drawn through median life B:Less scatter in shorter life region C:Elastic behavior D:A discontinuity or “knee” 3. The correct conclusions are as follows （ ）
A:The tension mean stress is beneficial B:The compressive mean stress is detrimental C:The compressive mean stress is beneficial D:The tension mean stress is detrimental 4. This cyclic creep decreases the detrimental effects of tensile mean stress on fatigue life. （ ）
A:错 B:对 5. Fatigue limit has ranged from 1to 70 percent of ultimate tensile strength. （ ）
A:对 B:错