Applicability of SSB-iFEM for deformation reconstruction of stiffened box girders under single-sided sensor configurations

Accurate deformation reconstruction of box girders is essential for ship structural health monitoring, but installing strain sensors on both surfaces of structures is often impractical. This study investigates the applicability of the single-sensor-based inverse finite element method (SSB-iFEM) to stiffened box girders under single-sided sensor configurations. The numerical model is established to compare different sensor configurations, evaluate performance under different loading conditions, and to analyze the effects of structural parameters on reconstruction accuracy, while a four-point bending experiment provides supplementary validation. The results show that the inner-side sensor configuration provides significantly better reconstruction accuracy than the outer-side configuration. For the baseline model, the inner-side configuration achieves a mean absolute error (MAE) of 0.55% and a maximum error of 2.61%, while maintaining MAEs below 0.7% under all considered loading conditions. Deck thickness has a non-monotonic effect on reconstruction accuracy, whereas increasing stiffener thickness reduces error and leads to convergence. Increasing stiffener number only slightly increases overall error but enlarges local error concentrations near stiffened regions. Experimental results further support the feasibility of SSB-iFEM under a partially single-sided measurement condition.