- Cyclic stabilization is usually reasonably complete within 10 to 40 percent of the total life. （ ）
- Stress relaxation is the same as the cyclic softening. （ ）
- Fatigue limit is associated with the material defect (inclusion). （ ）
- Higher frequencies typically allow more environmental interaction to occur. （ ）
- The fatigue process is elastic deformation and fatigue crack usually initiates from elastic straining in localized region. （ ）
- The da/dN model requires the use of fracture mechanics. （ ）
- Fine-grain materials tend to give lower fatigue resistance, while coarse-grain materials give higher creep resistance. （ ）
- A crystallite is a small or even microscopic crystal which forms. （ ）
- Very short life and very long life data are not included in data fits. （ ）
- Most of fatigue failures are unexpected. （ ）
- Fatigue induced mechanical failure is a very important factor in the engineering design. （ ）
- VHCF Failure modes are related to surface conditions, environmental effects, materials, applied number of cycles, etc. （ ）
- Crack growth rates are initially high but decrease, with the decreasing crack length. （ ）
- Hydrogen embrittlement is often found in some high strength steels. （ ）
- The modified Goodman curve or the Gerber curve, is conservative for high temperature unnotched mean stress effects. （ ）
- The characteristics of ductile fracture include （ ）
- The S-N behavior can be affected by many factors （ ）
- Three principle parameters in Haigh diagram, as follows （ ）
- The understanding of oxidation is correct as follows （ ）
- Several empirical equations used for evaluating mean stress effect include （ ）
- Parameters in the notch effect should be considered, as follows （ ）
- The following mechanical properties are usually obtained from monotonic tension test（ ）
- Keywords in the definition of fatigue include （ ）
- The characteristics of General S-N behavior are as follows （ ）
- Factors of influencing strain-life behavior include （ ）
- In general, fatigue resistance for a given metal in an air environment tends to （ ） as the temperature increases
- The feature of excess deformation does not include （ ）
- The feature of safe-life design include （ ）
- A larger fraction of life for crack nucleation occurs （ ）
- The hysteresis loops at high temperatures are （ ）
- Which is the feature of small crack （ ）
- The feature of corrosion generally does not include （ ）
- The correct statement is as follows （ ）
- The number of beach marks is related to （ ）
- About plane strain, the correct statement is as follows （ ）
- Metal’s hardening or softening during cyclic deformation can occur （ ）
- Two fracture modes are in dependent on （ ）
- The feature of brittle fracture does not include （ ）
- Fatigue behavior and life predictions are more complicated at high temperatures because of （ ）
- Both frequency and temperature will affect the fatigue resistance of materials. （ ）
- The High-temperature fatigue is （ ）
- Temperature influence on fatigue strengths （ ）
- The description of Neuber’s rule is as follows （ ）
- As the hold time increased, the life decreased drastically at both test strain ranges. （ ）
- The notched fatigue strength maybe a greater fraction of the smooth fatigue strength. （ ）
- Three principle parameters in Haigh diagram contain （ ）
- The incorrect statement is （ ）
- Which is not the characteristic of typical loading mode or crack mode（ ）
- Two stress condition contain （ ）
- The limiting conditions for LEFM are as follows （ ）
- The increasing R ratio has a tendency to increase the crack growth rates. （ ）
- The crack can be closed during unloading while the specimen is still under a positive tensile stress. （ ）
- The characteristics of hysteresis loop are as follows （ ）
- The correct conclusions about data fitting are as follows （ ）
- The rate or amount of relaxation depends on the magnitude of plastic strain amplitude. （ ）
- Incremental-step test method: A series of specimens, each of which is subjected to a constant strain amplitude. （ ）
- Which is not the characteristic of unloading （ ）
- This cyclic creep decreases the detrimental effects of tensile mean stress on fatigue life. （ ）
- The correct conclusions are as follows （ ）
- Fatigue limit has ranged from 1to 70 percent of ultimate tensile strength. （ ）
- Which is not the characteristic of real fatigue Limit （ ）
- The characteristics of beach mark are as follows （ ）
- Which is not the characteristic of slip （ ）
- Modes of fatigue crack growth with fracture are as follows （ ）
- Crack nucleate at surface and grow across several grains (stage I, microcrack), and then to grow in a zigzag manner (stage II, macrocrack). （ ）
- The mechanical property of each grain is the same. （ ）
- Analysis needs to be confirmed by tests. （ ）
- Allowable service life should be less than test or calculated life. （ ）
- The characteristics of fail-safe design is （ ）
- The main points of damage tolerance design are as follows （ ）
- Four kinds of possible design situations are as follows （ ）
- The contribution of August Wöhler is as follows （ ）
- Excess deformation is （ ）
- The correct statement of fatigue includes （ ）
- Proper fatigue design includes synthesis, analysis and testing. （ ）
- Failure due to fatigue, i.e. repeated loading, is the most common cause of mechanical failure. （ ）
答案:对
答案:错
答案:对
答案:错
答案:错
答案:对
答案:错
答案:对
答案:对
答案:对
答案:对
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