On the Resistance of Cruciform Structures during Ship Collision and Grounding
School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
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J. Mar. Sci. Eng. 2023, 11(2),
Received: 29 December 2022 / Revised: 1 February 2023
/ Accepted: 15 February 2023 / Published: 20 February 2023
(This article belongs to the Special Issue
Abstract
This paper presents an experimental, numerical, and analytical study of a novel specimen subjected to local in-plane load, to investigate its crushing deformation and resistance. The specimen was designed and fabricated to simplify the cruciform structure in double-hulled vessels subjected to external loads during collision and grounding incidents. The study results will provide reliable insights into grounding scenarios as well as side collision scenarios of double-hulled vessels. A quasi-static indentation test and related numerical research showed good agreement regarding deformation mode and force–displacement response. On the basis of the experimental and numerical results, an analytical method is proposed to derive the deformation energy, the instantaneous resistance, and the mean resistance of the deformed structure. The analytical method was verified with recorded test data and a nonlinear finite element analysis. It enables a rapid assessment of the response of the structure under accidental loads, which is a guideline for the design of crashworthy hull structures and the assessment of their crashworthiness.
1. Introduction
Ship collision and grounding accidents may cause catastrophic consequences such as casualties, economic losses, and environmental pollution [1]. According to the statistics of the International Oil Tanker Owners Oil Pollution Federation (ITOPF), 62% of large spills (over 700 tonnes) recorded between 1970 and 2021 were caused by collisions and groundings [2]. In order to reduce losses caused by impact accidents, it is essential to develop procedures to assess double-hull tanker performance in collision and stranding accidents.
Cruciform structures in double hulls consist of joints between side stringers and transverse webs in a double side, as well as longitudinal girders and transverse frames in a double bottom. Figure 1 shows a typical collision and grounding scenario for a double-hull vessel: the bulbous bow of the collision ship and rock are simplified into rigid hemispheroid, and cruciform structures connected with outer panels suffer local axial compression load in the schematic. During the ship collision and grounding, the cruciform structure acts as one of the main structures resisting the deformation and absorbing the impact energy. Therefore, it is essential to investigate the deformation mechanism, energy absorption, and resistance of cruciform structures under in-plane loading.