详细介绍了GB/T 228.1-2010中方法A中两种不同类型的应变速率控制模式。第一种应变速率Le是基于引伸计的反馈而得到;第二种是根据平行长度估计的应变速率Lc，即通过控制平行长度与需要的应变速率相乘得到的横梁位移速率来实现;同时给出了第二种应变速率Lc与传统的十字头分离速率(有人称方法C)的技术差异。

Two different types of strain rate control mode were described. The first is the control of the strain rate itself, Le, that is based on the feedback obtained from an extensometer. The second is the control of the estimated strain rate over the parallel length, Lc, which is achieved by controlling the crosshead separation rate at a velocity equal to the desired strain rate multiplied by the parallel length. At the same time, the difference between the estimated strain rate over the parallel length, Lc, and traditional crosshead separation (method C) was offered.