when forces are applied to them.

所表现出的特性也进行了理想化
If you continue to add force, then at some point

如果你持续施力总有一刻
the material's not going to behave perfectly elastically anymore.

材料就不再发生理想弹性形变
You'll see that because it's not a straight line anymore,

你会看到图线不再是一条直线的了
it's not linear.

这条线不再是直线型的
It still might be elastic but it's not linearly elastic

尽管仍然有弹性但不是呈线性弹性了
so you can't describe it by just the slope anymore.

因此你不能再单单用斜率来形容弹性
At some point, for any material,

某种程度上说对于任何材料来说
you could enough weight that it's going to fail.

只要给与足够的砝码终究会发生崩溃
You could define the stress at failure,

当材料本身破碎时可以定义为应力破坏
when the material physically breaks, or the strain at failure

当材料本身无法再发挥其正常功能时
when it physically doesn't function as a material anymore;

可以定义为应变破坏