Which of the following states should be checked as the normal service limit state. ( ) A: The structure is out of balance as a rigid body B: Partial damage that affects the durability C: Not suitable to continue to bear the load any more due to excessive plastic deformation D: The component loses stability

在陈述某研究的价值时，哪种说法较为恰当？ A: The research will help to understand deformation processes. B: The research can help to understand deformation processes. C: The research may help to understand deformation processes. D: The research should help to understand deformation processes.

For plane bending the characteristics of deformation are ( ). A: The cross section remains plane when bent; B: The axis after deformation is a plane curve; C: All external loads act on the same plane; D: The axis after deformation is in the same plane with the loading plane.

What generalizations can be made about the recrystallization temperature with respect to(a)the degree of deformation,(b)the temperature,(c)the time of heating at temperature,(d)the final grain size,and(e)the purity of the metal?

The<br/>safety coefficient of the capacity of composite materials is usually<br/>____ times of metal materials. A: 0.8-0.9 B: 1.0-1.25 C: 1.15-1.2 D: 1.5-2.0