Fatigue Life Design of Mechanical Structure答案2023

第五章测试

1. Which is not the characteristic of typical loading mode or crack mode（ ）
A:Opening mode B:Tearing mode C:Sliding mode D:Fatigue fracture
答案:D
2. Two stress condition contain （ ）
A:Plane stress B:Rotating bending C:Axial loading D:Plane strain 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:The plastic zone size at the crack tip must be smaller relative to the crack length C:Should be under cyclic loading 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:错 B:对 5. The crack can be closed during unloading while the specimen is still under a positive tensile stress. （ ）
A:错 B:对