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.

Generally, ductility coefficient of a structure is defined as the ratio of maximum allowable deformation and yield deformation of a member or structure when the bearing capacity of the structure is not less than ( ) of its ultimate bearing capacity. A: 70% B: 80% C: 85% D: 90%

An axial compressive force F＝Fcr is acting on an ideal column in linear equilibrium. And then the column produces the bending deformation due to a small lateral disturbing force. If the disturbing force is removed at this time, ( ) . A: The bending deformation will disappear and return to a straight line B: The bending deformation is reduced and the straight line shape can not be restored C: The bending state is not changed D: The bending deformation continues to increase

理想弹性材料，在应力作用下会发生弹性形变（Elastic Deformation）,其应力与应变关系服从 定律。 A: 胡克 B: 牛顿第一定律 C: 牛顿第三定律 D: 牛顿流体定律

变形的英文表达为 A: Deformation B: Stress C: Strain D: Displacement