Reducing the Influence of Localized Large Stiffness Compartments in Longitudinal Bending Moment Identification

The capability of hulls to withstand longitudinal bending moments has been a subject of continuous research. Longitudinal bending moment identification is an essential aspect of the ship structural health monitoring. This study aims to investigate the effect of localized large stiffness compartments on the accuracy of longitudinal bending moment identification and proposes an effective method to improve this accuracy. A numerical study is carried out with a box-beam model as the research object to investigate in detail the effect of localized large stiffness compartments on the spatial distribution of model stresses, and a modified method of longitudinal bending moment identification with correction coefficient is introduced to mitigate the impact of localized large stiffness compartments on identification accuracy. Numerical results indicate that localized large stiffness compartments have a significant impact on the side stress distribution of the model. The stress distribution above the top deck of the compartment is linear, while below it is nonlinear, making it challenging to achieve the desired identification accuracy using longitudinal bending moment identification based on hull bending theory. Compared with the conventional method, the modified method can significantly improve the identification accuracy of the longitudinal bending moment under the localized large stiffness compartment structure, with identification error below 5%. Therefore, implementing this method in practical engineering is highly promising and has broad application prospects.