A new constant amplitude equivalent principal component analysis-based method for non-proportionality quantification of variable amplitude loaded welded joints in large-scale structures

The levels of non-proportionality in fatigue stress-time series are difficult to determine. Approaches from literature not easy interpret and predicts different for variable constant amplitude stresses. In this paper, an extension the PCA-based method is proposed which stresses transformed into equivalent by scaling stress reversal points. This ensures robust easily interpretable results. compared with other approaches given using published experiments a designed offshore jacket structure. results show that can predict accurately.