PSI - Issue 5

Jung Min Sohn et al. / Procedia Structural Integrity 5 (2017) 943–950 Aditya Rio Prabowo et al. / Structural Integrity Procedia 00 (2017) 000 – 000

944

2

Nomenclature Ė b

the rate of bending energy dissipation the rate of dissipated energy in the crack tip zone

Ė c Ė f Ė m Ė p

the rate of dissipated energy by frictional forces on the surface of the structure

the rate of membrane energy dissipation the rate of dissipated plastic energy

F H the resisting force of the structure in the direction of V . This direction is assumed to be horizontal F P the so-called plastic resistance which here includes both plasticity and fracture F vm the von Mises’ plane stress N αβ the membrane force tensor M αβ the bending moment tensor p the normal pressure on the rock from the plate element dS S the contact area between rock and plate V the relative velocity between ship and rock V rel the relative velocity between rock and plate element, dS ε̇ αβ the corresponding generalised strain rate in the deformed configuration κ̇ αβ the corresponding generalised curvature rate in the deformed configuration μ the Coulomb coefficient of friction σ 0 the uniaxial yield stress – average flow stress σ xx the direct stress in x-direction σ xy the shear stress in xy-plane σ yy the direct stress in y-direction σ zz the direct stress in z-direction Ship is the main transportation for export-import activity. It has various capacities and reasonable delivery time, which makes this transportation mode flexible to be used depending on situation (cargo type and size) and condition (sailing route) that are demanded by client. In this case, safety is the top priority to ensure cargo, crew and ship can arrive to a destination in good condition. There is a challenge to obtain the satisfaction in delivery time considering accidental loads that may be experienced by the ship. Statistical data of the International Oil Pollution Funds (IOPCF, 2005) showed that from ten forms of accident on the sea, approximately 23% of oil spill occurred after grounding impact. Moreover, a famous catastrophe of the Exxon Valdez in Alaska and ship a grounding case of the MV Drake in Australia indicate that serious attention should be given to ship grounding cases. Tanker is an important subject in grounding since the oil (tanker’s cargo) can be spilled after impact and can massively influence or even destroy ecosystems surrounding the grounding location. In case of the Exxon Valdez , extinctions of animals and vegetation were unavoidable and its effect to Alaska’ s water territory existed for decades. As its nature as an accidental phenomenon, ship grounding is observed by wide range of researchers as its occurrence and scenario may be different to each other. Results of these studies are always needed due to structural development and safety demand. In this study, a series of ship grounding models are determined. Impact location is focused to observe detail behavior of structural component on the target ship including its failure process. Structural damage in process of impact between ship structure and seabed is presented and correlations of the damage with other structural responses are summarized. 1. Introduction

2. Review on impact phenomena

Ship grounding needs to be carefully estimated so that the casualties after this event takes place can be controlled and anticipated as soon as possible. Relation of grounding and other accidental impact is close especially with ship collision and ice-structure interaction. In this section, a brief review to observe pioneer works of impact phenomena and development and a fundamental theory to assess ship grounding are presented.