Structural Damage Detection Through Finite Element Model Updating Using Strain-Based Auto/Cross-Correlation Function Data

This paper proposed a new sensitivity equation for updating Finite Element Models (FEM), based on the auto/cross-correlation function of strain data. While most of FEM updating approaches rely on data measured at structural nodes (degrees of freedom), the strain-based methods demonstrate the utility of element-level data. Strain data are more sensitive to localized damage than displacement responses. Therefore, the auto/cross correlation functions of the structural strain response data are employed to formulate an improved sensitivity equation applicable for model updating and damage detection purposes. The presence of both auto and cross terms provides the abundant data, thereby significantly enhancing the accuracy of the model updating results. The effectiveness of the proposed method is investigated by a three-dimensional jacket offshore platform model. Practical challenges in real-world conditions, including incomplete measurements, hydrodynamic and marine growth effects, model uncertainty, and errors in structural loading and response measurement are addressed. A comparative analysis is conducted across scenarios utilizing the auto-correlation of strain data, the auto/cross-correlation of strain data, and strain data only. The results indicate that using of auto/cross-correlation of strain data yields more accurate and reliable structural parameters compared to the alternative approaches.