A method for structural damage detection considering scour depth under the pile-soil interaction.

The structure of an offshore wind turbine accumulates damage during its service life, while its surrounding soil is continually scoured. However, the existing damage detection technique based on structural mode ignores scouring, which will cause damage misjudgment in engineering application. Therefore, the effect of scour depth on structural damage detection need to be studied urgently. In this paper, the pile and its surrounding soil are constructed into a vibration system, and the change of soil constraint state caused by scouring is reflected in structural mode. Based on that, a new structural damage detection method considering the pile-soil interaction is developed, which is suitable for engineering reality. Then, from a comparison between the calculated result and preset damage in the numerical simulations and model experiments, the proposed method is validated. The results show that the interference factors caused by scouring increase with the increase of scour depth, which causes the deterioration of damage identification effects gradually, and even masks the preset damage in the end. Finally, an optimized FE model based on the actual scour depth is presented, which reduces the number of interference factors and improves the effect of damage detection significantly. • A structural damage detection method considering pile-soil interaction and seabed scouring is proposed, which breaks through the limitations of the fix-end constraint. • This method can identify the damage of the structure under the constraint state that is closer to the actual scoured seabed, which is more meaningful for engineering. • The interference caused by scour increases with the increase of scour depth, which causes the deterioration of damage identification effects, and eventually masks the preset damage. • An optimized FE model based on the actual scour depth is presented, which improves the effect of damage detection significantly. [ABSTRACT FROM AUTHOR]