因此，物体热胀冷缩现象是产生热应力的前提。

Therefore the object is to produce the phenomenon of thermal expansion and contraction of the premise of thermal stress.

youdao

于是哪怕仍存在热胀冷缩的现象，所有的部件发生这一现象的比率都是相同的。

So while we still have expansion and contraction, all of the components expand and contract at the same rate relative to one another.

youdao