Progressive Collapse Analysis of the Local Elements and Ultimate Strength of a Ro-Ro Ship

Abstract

One of the most important criteria in ship design is strength. When a ship is under external loads such as waves, buoyancy or pressure, its internal reaction must resists those external loads. In this regard, external loads are retained by the hull girder, whose cross section is composed of plates and stiffeners, which have a significant influence on ultimate strength, especially in the longitudinal direction. Therefore, this strength must be assessed and evaluated for the ship structure and functional requirements. In this study, local elements of the ship cross section, such as plates and stiffeners, are analyzed, including their progressive collapse behavior. The example used for the calculation is a Roll-on/Roll-off (Ro-Ro) ship. The analysis is performed by assuming that the cross section remains plane and a one-frame space is considered. To calculate the ultimate strength of the Ro-Ro ship under hogging and sagging conditions, Smith's method is used and applied to an in-house program. The applied moment is given on the Multi Point Constraint (MPC) as the reference point of the neutral axis position. In this MPC position, a simple support is attached. The calculation of ultimate strength is made under hogging and sagging conditions, and the intact condition is focused on for the simple calculation. Welding residual stress, cracks, corrosion and initial deflection are not taken into account. Application of the FE method is also made to investigate the characteristics of the collapse mode for local elements and global structure, including ultimate strength.

Analisis kekuatan struktur ramp door haluan pada kapal Ferry Ro-Ro 1500 GT dengan variasi beban menggunakan Finite Element Method

“…Pada kapal Ro-Ro terdapat geladak mobil sebagai salah satu struktur konstruksi vital, karena digunakan untuk menopang beban kendaraan di atasnya [1]. Geladak feri ditempati dengan muatan yang berbeda; misalnya, geladak bawah menampung kendaraan dan kargo [2]. Dalam kajian perkembangan teknologi feri ro-ro, artikel yang paling banyak diulas berkaitan dengan keselamatan karena: feri ro-ro lebih rentan dibandingkan kapal dagang lainnya karena masalah berikut: (a) masalah stabilitas (b) freeboard rendah, (c) pintu akses kargo, (d) kurangnya sekat, (e) akses ke peralatan penyelamat (f) kerentanan cuaca buruk, (g) pengikatan kendaraan dan (h) proses pemuatan sehubungan dengan distribusi berat [3].…”

Comparison of the Ultimate Strength with and without Hatch Opening Subjected to Longitudinal Bending

“…The incidence of collision damage models on oil tanker and bulk carrier reliability was investigated by Campanile et al [4] by considering the IACS deterministic model against GOALDS/IMO database statistics for collision events, substantiating the probabilistic model. The progressive collapse analysis was performed by Muis Alie and Latumahina [5] for the local elements and the ultimate strength of a Ro-Ro ship. Van et al [6] focused on the effect of initial imperfections and corrosion related strength degradation of bulk carriers, the initial imperfections including initial distortions and residual stresses, are employed to assess the ultimate bending moment reduction.…”

Fatigue Analysis of 5000 GT Ferry Ro-Ro’s Car Deck Using Finite Element Method

“…The ferry decks are occupied with different loads; for example, a lower deck accommodates vehicles and cargo [4], Loading and unloading the vehicles use the Ramp Door with Ro-Ro (Roll On -Roll Off) system, which is designed at the bow or stern of the ship [5], Then the vehicles are accommodated in the lower deck or car deck. The car deck is subject to vehicle loads and should withstand heavy and repetitive loads.…”