Research On Ultimate Strength Of Damaged Bulk Carrier Based On Nonlinear Finite Element

The ultimate strength of the hull is an important indicator of the safety evaluation of the ship,and the study of the structural state of the damaged ship under the ultimate load is an indispensable link in the evaluation of the safety performance of the ship’s structure.At present,most of the assessments of the ultimate strength of damaged bulk carriers in various domestic and foreign regulations only consider the effect of vertical bending deformation.However,in the actual operation of the ship,especially when the ship is subjected to oblique and large-angle waves,the horizontal bending moment and torque generated by the wave excitation make the ship appear vertical deformation and significant horizontal and Torsion deformation.Under the combined action of vertical bending moment,horizontal bending moment and torque,the ultimate state of the hull structure will often undergo complex changes.Therefore,it is necessary to explore and analyze the ultimate strength evaluation of the hull structure in the environment of oblique waves and horizontal waves.This article mainly focuses on bulk carriers,and studies the characteristics and evaluation methods of the structural ultimate strength of the ship under different damaged conditions.According to the specification and analysis of the vulnerable location of the ship during actual operation,the typical damage pattern of the ship was determined.In the study,the finite element software ABAQUS was used to establish the finite element model of the midship compartment of the bulk carrier,and the non-linear finite element method was used to numerically simulate the damage process of the typical structure of the bulk carrier,and the damage process of the ship was obtained.Bending moment-turning angle curve and the ultimate bending moment value of the hull structure;the characteristics of the ultimate load-carrying capacity are analyzed through the statistics of the damage form of the typical bulk carrier and the ultimate bending moment under the intact ship.At the same time,by comparing the ultimate strength evaluation methods of various codes,a bending-torsion coupling control equation for the structural characteristics of bulk carriers is established,and a deterministic evaluation method for the ultimate strength of damaged bulk carriers based on combined bending moments is proposed.By using this method,the ultimate strength state of the bulk carrier under the typical damage mode is systematically evaluated.Studies have shown that it is necessary to take into account the influence of horizontal bending moment and torque on ultimate strength assessment under oblique and horizontal wave conditions when the ship’s operating data is sufficient,which can more effectively reflect the bulk carrier’s complex marine environment The ultimate strength state of the damaged structure is conducive to the refined design of the bulk carrier structure.