Fatigue Life Design of Mechanical Structure答案2023秋

第五章测试

1. Which is not the characteristic of typical loading mode or crack mode（ ）
A:Tearing mode B:Opening mode C:Sliding mode D:Fatigue fracture
答案:D
2. Two stress condition contain （ ）
A:Plane strain B:Axial loading C:Plane stress D:Rotating bending 3. The limiting conditions for LEFM are as follows （ ）
A:The net nominal stress in the crack plane must be less than the yield strength B:Should be under cyclic loading C:The plastic zone size at the crack tip must be smaller relative to the crack length D:The plastic zone size at the crack tip must be smaller relative to the geometrical dimensions of specimen or part 4. The increasing R ratio has a tendency to increase the crack growth rates. （ ）
A:对 B:错 5. The crack can be closed during unloading while the specimen is still under a positive tensile stress. （ ）
A:错 B:对