strain axis

例句：

1. 1.The stress axis is the line that runs through the center of the material.
   应力轴是穿过材料中心的线。
2. 2. The strain axis is the line that runs through the material's center.
   应变轴是穿过材料中心的线。
3. 3. The stress and strain axes are perpendicular to each other.
   应力轴和应变轴互相垂直。