This article aims to analyze the influence of high cycle fatigue damage
on the mechanical properties and low cycle fatigue performance of Q690D.
Monotonic tensile and cyclic loading tests were performed on Q690D
specimens with different degrees of high cycle fatigue damage.
Degradation models were established to describe the declining trending
of mechanical properties with the increase of pre-fatigue damage.
Manson-Coffin models for Q690D steels of different pre-damage levels
were established. Besides, a comparison was presented between Q690D and
Q355B. The research work in this article provides a fundamental
reference for the appropriate assessment of the mechanical performance
of Q690D high-strength steel structures after long-term alternating
loading.