In order to predict the residual longitudinal strength of damaged ship hull with initial elasto-plastic deformation, a semi-analytical method is presented in this paper. Based on the definition of effective area coefficient of damaged ship structural components, the influences of initial deformation on longitudinal strength are regarded as the reduction of section modulus of ship hull. Two typical kinds of stiffened plates for ship structures, namely the longitudinally and the transversally stiffened plates, are discussed respectively. Two numerical examples are presented and some conclusions have been drawn.
Damage analysis has been a focus in Structural Engineering in the past several decades. For a real life ship structure, It is inevitably damaged to some extent. The damage of ship structures is caused (I) by environmental conditions, (2) by improper loading cases, (3) and especially by accidental conditions, such as falling objects, collision, explosion, etc. The main types of damage usually include material aging, erosion. deformation, crack. and destroy. In this paper a semi-analytical method is presented to consider the influences of structural deformation on longitudinal strength. Since section modulus is widely used to characterize longitudinal strength of ship hull. the influences of damage can be regarded as a reduction of this parameter. Alternatively, since ship structures can be considered as a space beam-plate assembly, the calculation of section modulus of ship hull can be reduced to the calculation of effective areas of several stiffened plates. In the following discussion two typical kinds of stiffened plates for ship structures, namely the longitudinally and the transversally stiffened plates, are considered respectively. For longitudinally stiffened ship structures, the damaged area is reduced to several panels (plate-stiffener assemblies) with initial imperfections. Two essential damage models are considered and the influence of residual stress caused by damage is taken into account qualitatively.
