straight portion的意思|示意

The initial portion of the stress-strain diagram for most materials used in engineering structures is a straight line.

在工程结构中使用的大部分材料最初的应力应变图是直线型的。

I think this whole portion would be fine, so we could take this point as well as this point, because anywhere on this straight line, you will get the same value for Young's modulus.

我认为这个位置可以，所以我选择这个点，以及这个点，因为这条线的任意处，你都会得到相同的，杨氏模量。

The initial stable portion of this plot for most wellbores is a straight line, within the limits of the measurements.

对大部分井眼而言，该曲线的初始稳定部分都是直线，在测量的限度以内。