These stress concentrations are where most fatigue cracks occur.

这些应力集中是大多数疲劳裂纹发生的地方。

But, if not carefully performed, the welds have the potential to introduce flaws from which a fatigue crack can propagate.

但是，如果不小心执行，焊缝有可能引入缺陷，从而导致疲劳裂纹扩展。

If not caught, a fatigue crack will eventually reach a critical size where it can propagate rapidly, leading to a fracture.

如果不及时发现， 疲劳裂纹最终将达到临界尺寸， 并能迅速扩展，导致断裂。

The Federal Highway Administration recommends that, when a fatigue crack is found, a special, in-depth inspection be performed to look for more.

联邦公路管理局建议，当发现疲劳裂纹时，应进行专门的深入检查以寻找更多裂纹。