Investigation of torsion, warping and distortion of large container ships

Abstract

Abstract. Large deck openings of ultra large container ships reduce their torsional stiffness considerably and hydroelastic analysis for reliable structural design becomes an imperative. In the early design stage the beam model coupled with 3D hydrodynamic model is a rational choice. The modal superposition method is ordinary used for solving this complex problem. The advanced thin-walled girder theory, with shear influence on both bending and torsion, is applied for calculation of dry natural modes. It is shown that relatively short engine room structure of large container ships behaves as the open hold structure with increased torsional stiffness due to deck effect. Warping discontinuity at the joint of the closed and open segments is compensated by induced distortion. The effective torsional stiffness parameters based on an energy balance approach are determined. Estimation of distortion of transverse bulkheads, as a result of torsion and warping, is given. The procedure is illustrated in the case of a ship-like pontoon and checked by 3D FEM analysis. The obtained results encourage incorporation of the modified beam model of the short engine room structure in general beam model of ship hull for the need of hydroelastic analysis, where only the first few natural modes are of interest.

A Comprehensive Analysis of Structural Alternatives and Local Opening for a 2000 TEU Green Methanol-Powered Container Vessel

“…The assessment of a ship's structural integrity is contingent on various factors. Senjanovic et al [11] delved into the influence of torsional stiffness in the engine room using an energetic approach involving the modeling and simplification of the main deck as a beam affected by shear stresses.…”

New first order shear deformation beam theory with in-plane shear influence

“…Three recently published books give a good review of those theories [3][4][5]. Complex problem of coupled flexural and torsional vibrations of beam-like structures as ship hull with multi-cell cross-section and variable properties is presented in [6,7].…”

Metodología para el diseño a fatiga del reforzado transversal de un portacontenedores tipo Malacca Max

“…En 2009, Senjanovic et al [31] presentan un modelo mejorado, a partir de la teoría de vigas, para analizar secciones transversales de pared delgada y, se aplica a una barcaza prismática para estudiar la influencia de la posición del centro de esfuerzos cortantes. En 2011, Senjanovic et al [32] analizan el dominio de la longitud de la cámara de máquinas sobre el fenómeno de la torsión, en etapas tempranas del proyecto, mediante un modelo de vigas acoplado a un modelo hidrodinámico 3D, cuya solución se obtiene a partir de la superposición modal.…”

“…Choi [76] estudia el diseño estructural de un buque portacontenedores de 13.100 TEU, construido en el astillero Hyundai Heavy Industries 32 , donde se investiga el efecto del fenómeno de springing en la formulación del daño a fatiga para distintas ubicaciones (Figura 11). En línea con la investigación anterior, Andersen y Jensen [77] investigan la contribución del springing y whipping sobre el daño a fatiga de un buque portacontenedores de 9.400 TEU, a partir de la estimación del espectro de tensiones como alternativa al método de conteo Rainflow mediante un análisis espectral.…”

“…El módulo de alabeo es: sobre un elemento prismático, y a partir de la teoría de perfiles de pared delgada, se tiene que el momento torsor tiene dos componentes una pura y una de alabeo [32]:…”