What term refers to the repeated stressing of a surface?

The term that refers to the repeated stressing of a surface is fatigue. Fatigue is a failure mechanism that occurs in materials subjected to cyclic loading, meaning they experience repeated or fluctuating forces over time. This repeated stressing can lead to the initiation of cracks and ultimately result in material failure, even if the individual stress levels are lower than the material's ultimate tensile strength.

Understanding fatigue is crucial in engineering and material science, as it helps in predicting the lifespan of components under cyclic loads and designing them to resist such failures. Recognizing the signs of fatigue can lead to improvements in maintenance and operational practices, thereby enhancing the safety and reliability of structures and machinery.