loading stage

Loading stage model can be simplified for second-order large inertial system, which respond slowly; During no-load phase, the system respond quickly, but with large steady-state error.

加载阶段模型可化简为大惯性二阶系统，系统响应缓慢；空载阶段，系统响应迅速，但存在较大的稳态误差。

These differences are caused by different responses of strain on stress when rocks are under cycling load, which the phases of strain may be leading, lacking and lagging of stress phases in loading stage.

这是由这些岩石在循环载荷下应变相对应力的响应不同造成的，在加载阶段应变的相位可能超前、并行或者落后于应力的相位。

The deformation not only reflects the flexure behavior of slab at every loading stage, but also affects the stress status on the surface of punching shear cone and the ultimate capacity of the slab.

该变形反映了板在各个受力阶段的抗弯性能，也在很大程度上直接影响着冲切锥面上的应力分布和板的抗冲切能力。

According to the relation between the changes of the characteristics of the Acoustic Emission and stress condition, the sandstone and granite samples fracturing process both can be divided into three stages: the early loading stage, the medium loading stage and the late loading stage.

将砂岩和花岗岩样本的压裂过程和各自的声发射信号的规律的变化结合起来可以分为三个阶段，即加载初期阶段、加载中期阶段和加载后期阶段。并且它们具有各自不同的特征。

Results show that there are two peak values of the applied load during the loading stage. And the second peak value is corresponding to the initiation of steel bar yielding in Case 2. Then the calculated two peak values in Case 2 are verified with experimental results.

结果表明，加载过程中荷载将出现两个峰值，而对于钢筋发生屈服的情况，第二个峰值对应的是钢筋刚刚发生屈服时的荷载，该种情况下两峰值的计算结果得到了试验验证。