About 200–400 large merchant ships are decommissioned and scrapped every year. In addition, the U... more About 200–400 large merchant ships are decommissioned and scrapped every year. In addition, the US Navy decommissions tens of naval vessels every year. In 2002/2003, the average cost of custody for a ship to be decommissioned was $25,000 per year, and $2.5 million to scrap it. The US Navy budget to scrap naval vessels in 2002 was $33.4 million. Now apparently the Navy sinks naval vessels by bombs and torpedos. Scrapping can cause pollution, health hazards, accidents and threat to the ecosystem. Can a “polluting” ship about to be scrapped be used to generate clean wave energy? Maybe! It is possible to place the ship (unmanned) in about 50 m of water where deep-water swells may have an average wave period of 6–15 s. The ship would be “tuned” to have large motion response, particularly in heave and pitch. In short waves, the ship could serve as a platform for secondary energy absorption. The idea is to tune the ship to have rigid body resonance, or close to it, and resist that motion to absorb power. A hydraulic ramp connected to an accumulator feeding a hydraulic motor that generates power is one possibility. Several other energy extraction mechanisms such as turbines connected to oscillating water columns are possible devices. These concepts together with a few preliminary numerical analyses are presented and discussed.
29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 2, 2010
The aim of this study is to investigate the crashworthiness characteristics of steel-plated struc... more The aim of this study is to investigate the crashworthiness characteristics of steel-plated structures subject to low temperatures that are equivalent to the Arctic environment. Structural crashworthiness with regard to crushing and fracture is a key element in the strength performance assessment of ship collisions in the Arctic, which provides the primary motivation for the study. This article is a sequel to the authors’ previous paper [1]. In contrast to the previous paper, which dealt with test structures made of American Society for Testing and Materials (ASTM) A500-type carbon steel with the wall slenderness coefficient (b/t) of 37.5, the present paper considers grade A steel with the wall slenderness coefficient (b/t) of 25. Crushing tests are undertaken on square tubes subject to a quasi-static crushing load at both room and low temperatures. The effect of low temperatures on the material properties is examined on the basis of tensile coupon test results. The crushing behavio...
The perforation of mild steel, stainless steel and high-strength steel plates subjected to impact... more The perforation of mild steel, stainless steel and high-strength steel plates subjected to impacts characterised as low-velocity (up to about 20 m/s) and moderate-velocity (20–300 m/s, approximately) are examined in this paper, wherein recent experimental data and some empirical equations have been compared. The threshold velocity for the normal perforation of metal plates focuses on cylindrical projectiles with various shaped impact faces,
The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates s... more The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes mo...
Risk-based safety studies primarily aim to assess and manage the potential risks of accidental ev... more Risk-based safety studies primarily aim to assess and manage the potential risks of accidental events that may lead to fatality, asset damage, and environmental pollution. Such studies also include analyses of the effectiveness of escape ways, shelter or temporary refuge areas, and evacuation procedures. Two types of methodologies are relevant to risk-based safety studies, namely qualitative and quantitative approaches. The effects of the geometric and material nonlinearities of structural systems along with non-Gaussian aspects, multiple physical processes, multiple scales, and multiple criteria are precisely accounted for by quantitative approaches. Using qualitative approaches in safety studies does not provide sufficient accuracy. Therefore, quantitative approaches are much more appropriate for conducting advanced safety studies of structures and infrastructures. As such, this book focuses on quantitative approaches.
This chapter presents a practical method to investigate the effects of brittle fracture on the ul... more This chapter presents a practical method to investigate the effects of brittle fracture on the ultimate compressive strength of steel stiffened-plate structures under cryogenic conditions. Computational models are developed to analyse the ultimate compressive strength of steel stiffened-plate structures, triggered by brittle fracture, under cryogenic condition. A phenomenological form of the material model for the high-strength steel at cryogenic condition is proposed, that takes into account the Bauschinger effect, and implemented into a nonlinear finite element solver (LS-DYNA). Comparison between computational predictions and experimental measurements is made for the ultimate compressive strength response of a full-scale steel stiffened-plate structure, showing a good agreement between them.
About 200–400 large merchant ships are decommissioned and scrapped every year. In addition, the U... more About 200–400 large merchant ships are decommissioned and scrapped every year. In addition, the US Navy decommissions tens of naval vessels every year. In 2002/2003, the average cost of custody for a ship to be decommissioned was $25,000 per year, and $2.5 million to scrap it. The US Navy budget to scrap naval vessels in 2002 was $33.4 million. Now apparently the Navy sinks naval vessels by bombs and torpedos. Scrapping can cause pollution, health hazards, accidents and threat to the ecosystem. Can a “polluting” ship about to be scrapped be used to generate clean wave energy? Maybe! It is possible to place the ship (unmanned) in about 50 m of water where deep-water swells may have an average wave period of 6–15 s. The ship would be “tuned” to have large motion response, particularly in heave and pitch. In short waves, the ship could serve as a platform for secondary energy absorption. The idea is to tune the ship to have rigid body resonance, or close to it, and resist that motion to absorb power. A hydraulic ramp connected to an accumulator feeding a hydraulic motor that generates power is one possibility. Several other energy extraction mechanisms such as turbines connected to oscillating water columns are possible devices. These concepts together with a few preliminary numerical analyses are presented and discussed.
29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 2, 2010
The aim of this study is to investigate the crashworthiness characteristics of steel-plated struc... more The aim of this study is to investigate the crashworthiness characteristics of steel-plated structures subject to low temperatures that are equivalent to the Arctic environment. Structural crashworthiness with regard to crushing and fracture is a key element in the strength performance assessment of ship collisions in the Arctic, which provides the primary motivation for the study. This article is a sequel to the authors’ previous paper [1]. In contrast to the previous paper, which dealt with test structures made of American Society for Testing and Materials (ASTM) A500-type carbon steel with the wall slenderness coefficient (b/t) of 37.5, the present paper considers grade A steel with the wall slenderness coefficient (b/t) of 25. Crushing tests are undertaken on square tubes subject to a quasi-static crushing load at both room and low temperatures. The effect of low temperatures on the material properties is examined on the basis of tensile coupon test results. The crushing behavio...
The perforation of mild steel, stainless steel and high-strength steel plates subjected to impact... more The perforation of mild steel, stainless steel and high-strength steel plates subjected to impacts characterised as low-velocity (up to about 20 m/s) and moderate-velocity (20–300 m/s, approximately) are examined in this paper, wherein recent experimental data and some empirical equations have been compared. The threshold velocity for the normal perforation of metal plates focuses on cylindrical projectiles with various shaped impact faces,
The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates s... more The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes mo...
Risk-based safety studies primarily aim to assess and manage the potential risks of accidental ev... more Risk-based safety studies primarily aim to assess and manage the potential risks of accidental events that may lead to fatality, asset damage, and environmental pollution. Such studies also include analyses of the effectiveness of escape ways, shelter or temporary refuge areas, and evacuation procedures. Two types of methodologies are relevant to risk-based safety studies, namely qualitative and quantitative approaches. The effects of the geometric and material nonlinearities of structural systems along with non-Gaussian aspects, multiple physical processes, multiple scales, and multiple criteria are precisely accounted for by quantitative approaches. Using qualitative approaches in safety studies does not provide sufficient accuracy. Therefore, quantitative approaches are much more appropriate for conducting advanced safety studies of structures and infrastructures. As such, this book focuses on quantitative approaches.
This chapter presents a practical method to investigate the effects of brittle fracture on the ul... more This chapter presents a practical method to investigate the effects of brittle fracture on the ultimate compressive strength of steel stiffened-plate structures under cryogenic conditions. Computational models are developed to analyse the ultimate compressive strength of steel stiffened-plate structures, triggered by brittle fracture, under cryogenic condition. A phenomenological form of the material model for the high-strength steel at cryogenic condition is proposed, that takes into account the Bauschinger effect, and implemented into a nonlinear finite element solver (LS-DYNA). Comparison between computational predictions and experimental measurements is made for the ultimate compressive strength response of a full-scale steel stiffened-plate structure, showing a good agreement between them.
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