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Collaborating Authors
The Twenty-second International Offshore and Polar Engineering Conference
Study On Transmission Law of Flexural Waves Through L-shaped Steel-Aluminum Joints
Lin, Yongshui (School of Transportation / Key Laboratory of High Speed Ship Engineering, Ministry of Education, Wuhan University of Technology) | Wu, Weiguo (School of Transportation / Key Laboratory of High Speed Ship Engineering, Ministry of Education, Wuhan University of Technology) | Li, Xiaobin (School of Transportation / Key Laboratory of High Speed Ship Engineering, Ministry of Education, Wuhan University of Technology) | Gan, Jin (School of Transportation / Key Laboratory of High Speed Ship Engineering, Ministry of Education, Wuhan University of Technology)
ABSTRACT: The transmission law of flexural waves through L-shaped joints connected by two plates made of two different materials is studied by using the wave approach. The numerical simulation of transmission parameters of the steel-aluminum joint is carried out synchronously with MATLAB. The transmission law of flexural waves through Lshaped joints with different materials is compared with that of homogeneous material joints, which shows that there are some prominent differences between them. One of the most remarkable divergences is that the thickness ratio corresponding to the minimum transmission loss is not the same. The result of this paper is of important guiding significance for acoustic design and vibration wave impedance control of hybrid structure, especially for vessels with steelaluminum mixed structure. INTRODUCTION Except of being absorbed due to the damping loss, the elastic waves also undergo the loss, reflection, transmission, and wave conversion in the joints meanwhile. Cremer et al. (1988) analyzed both longitudinal and flexural waves transmission at normal incidence for different junctions, as well as flexural waves transmission for oblique incidence at a corner junction by wave approach. Budrin and Nikiforov (1964) used the line joint model to represent a junction by wave approach. Kihlman (1967) calculated the flexural wave transmission at symmetric cross junctions for the case of random incidence. Langley and Heron (1990) discussed the elastic wave transmission through plate/beam junctions. A generic plate/beam junction was considered. The junction consisted of an arbitrary of number plates which were either coupled through a beam or directly coupled along a line. Mccollum and Cuschieri (1990) calculated the power transmission at an L-shaped junction including both the effects of in-plane waves and rotary inertia and shear (Mindlin bending) in the plates. These references are cited only as examples, because there are numerous other works using this method (Che, 2008).
Study On Optimal Design of Bulbous Bow For Deep Sea Trawlers Based On Viscous Flow Theory
Xie, Yonghe (Department of Naval Architecture and Civil Engineering / Zhejiang Key Libratory of Ship Engineering, Zhejiang Ocean University) | Li, Gangqiang (Department of Naval Architecture and Civil Engineering / Zhejiang Key Libratory of Ship Engineering, Zhejiang Ocean University)
ABSTRACT: The bulbous bow is often designed to reduce the resistance of the deep sea trawlers. Firstly, the viscous flow around ship hull is simulated based on Computational Fluid Dynamics (CFD) software FLUENT. The Volume of Fluid method (VOF) has been used with FLUENT for capture the free surface around the ship at design speed. Experiment has been established in order to verify and validate the numerical results, and it shows that the simulation results reach agreement well with experiment results. Secondly, the reference length, the reference breadth and the reference height of bulbous bow are selected as the key variables to be optimized. The bow wave-making resistance mechanism will be studied by changing these variables and comparing the corresponding results. In this paper, thirteen models are calibrated at the design speed under working condition: change only the length of bulbous bow in the first five models while keep the breadth and the height unchanged; only change the height in the next three models, and finally change only the breadth in the last five models. In the final part, the optimized model is obtained, and then the total resistance force at the complete speed will be calculated and compared with the origin model. The study shows that the total resistance based on the optimized model has been greatly reduced if compared with the origin model, especially at modern and high speed. INTRODUCTION In the preliminary design of ships, it is important to optimize and determine the ideal ship shape. When the ship heads in one direction, the wave making induced by the ship transmits and dissipates away from the hull. Meanwhile, the ship undergoes the opposite force. One of its components is known as the wave making resistance, which is the dominant among the total resistance force.
Numerical Simulation of Liquid Motion In SPB Tank
Kobayakawa, Hiroaki (Structural Engineering, Ship & Offshore Basic Design Department, IHI Marine United Inc) | Kusumoto, Hiroki (Structural Engineering, Ship & Offshore Basic Design Department, IHI Marine United Inc) | Toyoda, Masanobu (Structural Engineering, Ship & Offshore Basic Design Department, IHI Marine United Inc)
ABSTRACT: SPB tank is one of LNG tank types and it can avoid the resonance between internal liquid motion and ship motion by arranging internal structure. This paper describes validation study of simulation method for liquid motion analysis in SPB tank, sloshing experiment with large scale SPB tank model and numerical simulation of liquid motion in full-scale SPB tank. Through these studies, sloshing pressure in nonresonance condition is compared with that in resonance condition. These studies show that sloshing pressure is quite low level and simple CFD calculation can simulate it with sufficient accuracy in nonresonance condition. On the other hand, sloshing pressure is quite high level and it seems to be difficult to estimate it in resonance condition by simple CFD calculation. INTRODUCTION Many offshore gas fields are being discovered and developed due to increasing demand for clean and safe energy. Offshore gas storage systems have any level of partial filling conditions, which is generally severe in terms of sloshing. In fact, some incidents of damage to LNG tanks, such as Polar Alaska (1969), Arctic Tokyo (1971), Larbi Ben M'Hidi (1978), Catalunya Spirit (2006) and 3 Mark III ships (2008), was reported (Gavory et al., 2009). It was also reported that the damages were caused due to sloshing load and LNG filling height in tank played major role in sloshing intensity. Damage to LNG tank may cause wide-scale disaster and it should be averted. Furthermore recent large scale natural and man-made disasters brought the demands for preparation against unexpected situations and enhanced safety level to infrastructure industries. Therefore LNG tanks with non-resonance, the intrinsically safe containment systems, are desired. SPB tank system, developed by IHI (Fujitani et al., 1984), is one of LNG tank types and SPB means Self-supporting Prismatic Shape IMO type B.
- Asia > Japan > Kantō > Tokyo Metropolis Prefecture > Tokyo (0.25)
- North America > United States > Alaska (0.24)
- Research Report > New Finding (0.87)
- Research Report > Experimental Study (0.55)
Residual Longitudinal Strength Analysis of Ship¿s Hull Girder With Damages
Muis Alie, Muhammad Zubair (Department of Naval Architecture and Ocean Engineering, Osaka University) | Fujikubo, Masahiko (Department of Naval Architecture and Ocean Engineering, Osaka Universityy) | Iijima, Kazuhiro (Department of Naval Architecture and Ocean Engineering, Osaka University) | Oka, Saori (Department of Naval Architecture and Ocean Engineering, Osaka University) | Takemura, Kentaro (Department of Naval Architecture and Ocean Engineering, Osaka University)
ABSTRACT: An incremental formulation of the progressive collapse behavior of ship's hull girder with damages subjected to longitudinal bending is presented based on the Smith's method. The hull girder is modeled as a beam with asymmetric cross section subjected to biaxial bending. The explicit expression of the rotation and translation of the neutral axis due to the buckling and yielding of structural elements is given. The proposed formulation is applied to the residual strength analysis of bulk carriers and a tanker having collision damages at the side structures. Particular focuses are placed on the influence of the rotation of neutral axial on the residual hull girder strength and the solution procedures to obtain the residual strength including the case of biaxial bending. INTRODUCTION Ship's hulls may suffer collision or grounding damages, which may threaten safety of ships and surrounding environment. In order to enhance the structural safety of ships and reduce the associated risks, the International Maritime Organization (IMO, 2009) has required in the Goal Based Standard (GBS) to consider the residual strength of the hull girder in specified damaged conditions as one of the functional requirements for the structural rules for bulk carriers and tankers. Ultimate longitudinal bending strength is the most fundamental strength to ensure the safety of ships not only in the intact condition but also in the damaged condition. Many studies have been performed on the assessment of residual bending strength of hull girders with damages. Paik et al. (1998) developed a rapid procedure to identify the possibility of hull girder failure after collision and grounding damages based on the closed-form formulae of the ultimate hull-girder strength and section modulus after the damages. Wang et al. (2002) proposed a similar approach based on the section modulus.
- Asia > Japan (0.28)
- South America > Brazil (0.28)
- Transportation > Marine (1.00)
- Transportation > Freight & Logistics Services > Shipping (1.00)
Analysis of Bending Test of 40-in X70 Line Pipe
Chen, Hongyuan (China National Petroleum Corporation, Tubular Goods Research Institute, Key Lab of Oil Tubular Mechanical and Environmental Behaviour of CNPC, School of Materials science & engineering, Xian Jiaotong University) | Ji, Lingkang (China National Petroleum Corporation, Tubular Goods Research Institute, Key Lab of Oil Tubular Mechanical and Environmental Behaviour of CNPC, School of Materials science & engineering, Xian Jiaotong University) | Huang, Chengshuai (China National Petroleum Corporation, Tubular Goods Research Institute, Key Lab of Oil Tubular Mechanical and Environmental Behaviour of CNPC) | Wang, Haitao (China National Petroleum Corporation, Tubular Goods Research Institute, Key Lab of Oil Tubular Mechanical and Environmental Behaviour of CNPC) | Li, Yanhua (China National Petroleum Corporation, Tubular Goods Research Institute, Key Lab of Oil Tubular Mechanical and Environmental Behaviour of CNPC)
ABSTRACT: This paper presents the research on the bending strain capacity of 40" X70 Line pipe. Full-scale test of pressurized pipe of specific design factors was conducted to demonstrate the compressive strain limit. The numerical analysis based on laser measurement, reverse engineering and finite element method was also performed to investigate the pipe buckling behavior. The results of full-scale test imply that finite element method can predict buckling strain of bent pipe effectively. INTRODUCTION Strain-based design refers to pipeline design methodologies to maintain pipeline safety and integrity under large plastic deformation (often defined as total strain greater than 0.5%) (Mohr, 2003). It encompasses both strain demand (applied strain) and strain capacity (strain limit). There are at least two limit states related to SBD: tensile rupture and compressive buckling, which are always considered as ultimate limit state and service limit state, respectively. The tensile rupture leads to breach of pressure containment or deformation boundary and hence very serious. The compressive buckling does not lead to failure of materials directly, but if a rupture occurs due to the local buckling, the consequence is as same as the tensile rupture. The cases depend on the degree of wrinkling result in buckling. Although slight wrinkling can be tolerated during pipeline service, however, local buckling is considered as a kind of failure of pipelines. For the pipelines through permafrost or seismic areas, it is necessary to demonstrate the strain capacity of pipelines under the bending deformation to keep the integrity of pipeline during laying and service (Suzuki and Endo, 2001). It is also an important part of strain-based design methodology. In general, plastic strain concentration develops when local buckling occurred on pipelines after continuous bending. The buckling strain can be evaluated by the ways of full-scale bending test and Finite Element method.
- Asia > China (0.51)
- Asia > Middle East > Israel > Mediterranean Sea (0.24)
Effect of Full Scale Pipe Bending Test Method On Deformability Results of SAW Pipes
Shitamoto, Hidenori (Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd) | Hamada, Masahiko (Pipe and Tube Company, Sumitomo Metal Industries, Ltd) | Takahashi, Nobuaki (Pipe Dept. Kashima steel works, Sumitomo Metal Industries, Ltd) | Nishi, Yuki (Pipe Dept. Kashima steel works, Sumitomo Metal Industries, Ltd)
ABSTRACT: In recent years, the construction of high-pressure gas pipelines with API X80 grade submerged arc welding (SAW) pipes is progressing for the improvement of transportation efficiency. However, it is generally known that the deformability of the SAW pipes is decreased by increasing strength of the pipes. Therefore, application of strain-based design (SBD) has been discussed primarily by the demand of construct pipelines in permafrost regions and seismic regions. It is important to understand the deformability of the SAW pipes, and the full scale pipe bending tests are performed as one of the evaluation method. Though a lot of test methods exist in the full scale pipe bending test, standardization of the test method is not done. In this study, two kinds of different full scale pipe bending tests by using the same X80 SAW pipes and finite element analysis (FEA) were performed to investigate the effect of the test methods on the evaluation results of the pipes. INTRODUCTION High strength line pipe for gas transmission pipeline has been developed for cost reduction of gas transportation by high pressure operation. The applicability of high strength line pipe has been studied by full scale trial of construction and burst test (Demofonti, 2004; Macia, 2004). As the ductility of steel decreases in high strength line pipe, the deformability of line pipe related to strain capacity of pipeline has been focused on the application of high strength line pipes for high-pressure gas pipelines. In recent years, studies on buckling strain limit of the line pipe were performed by full scale bending test (Shitamoto, 2009; Tsuru, 2010; Mannucci, 2011; Tajika, 2011). However it is thought that the buckling strain limit value obtained by the bending test depends on the pipe bending test method.
ABSTRACT: In the wake of the recent events, deep water owners and operators are challenged to provide improved asset integrity monitoring. Also, as offshore deployments go deeper and further it is increasing the burden on subsea power requirements and structures that deliver this needed energy. Hence, subsea power umbilicals need to integrate larger power conductors with longer tiebacks and greater depths. In this paper, a new method of monitoring the stress/strain and temperature events of these power umbilicals is discussed. Aker Solutions and Omnisens have embedded a fully distributed fiber optic strain and temperature sensor within an umbilical. By illuminating the sensor with a DITEST (Distributed Temperature and Strain) Brillouin Optical Time Domain Analyzer, a sensor is demonstrated for manufacturing verification, installation/deployment certification, and continuous integrity monitoring. INTRODUCTION Chevron is interested in maximizing operational efficiency and reducing the risk of failure, accidents, or downtime within their subsea structures. Aker Solutions and Omnisens SA set forth on those directives in the development, integration and validation of a fully distributed fiber optic strain and temperature sensor for a prototype power umbilical. The goals of this project were to incorporate a monitoring system that improves construction validation, provides installation certification and feedback, and allows permanent on-line temperature and strain monitoring of this high power, long tieback, power umbilical in deep water. By using a distributed sensing technique known as Brillouin Optical Time Domain Analysis (BOTDA), Omnisens developed a dedicated fiber optic strain and temperature sensor cable (hereafter referred to as the sensor) that can be directly integrated into the umbilical manufacturing methods developed by Aker Solutions. The embedded fiber optic cable becomes an integral, fully distributed strain and temperature sensor when illuminated by the Omnisens' Brillouin BOTDA known as the DITEST sensing system, capable to monitor very long structures.
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 759 > Jack-St Malo-Big Foot Field > Wilcox Formation (0.99)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 758 > Jack-St Malo-Big Foot Field > Wilcox Formation (0.99)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 678 > Jack-St Malo-Big Foot Field > Wilcox Formation (0.99)
ABSTRACT: A phenomenological cyclic plasticity model with the damage counting parameter, proposed for the description of the cyclic loading behavior of typical carbon steels during low- and high-cycle fatigue subjected to stressing both lower and higher than the dominant yielding stress, is applied for the prediction of cyclic softening phenomena and crack initiation life under the symmetrical fatigue loading condition with and without multi-step changes of the applied stresses. INTRODUCTION Among fatigue failure processes of materials, prediction of fatigue initiation as a series of damage accumulation and crack initiation is one of the most challenging issues, whilst crack initiation is mainly subjected to the damage accumulation which would macroscopically and/or microscopically take the form of the cyclic plasticity behavior represented by hysteresis loop and ratcheting (c.f. Suresh (1998); Dunne (2007); Toyosada (2004)). For the purpose of describing and evaluating the mechanical fatigue processes of materials, various cyclic plasticity models have been proposed up to the present (e.g. Mroz (1967); Dafalias and Popov (1975); Dafalias and Hermann (1980); Hashiguchi (1989); Ohno and Wang (1993); Tsutsumi and Hashiguchi (2005); Tsutsumi (2007), (2008); Tsutsumi et al. (2008)). Many of these models are originally designed for the simulation under relatively larger stress amplitude than the macroscopic yielding state, which would often categorized into low- or extremely low-cycle fatigue phenomena. Some experiments, focused on the damage accumulation observed in the stress-strain relationships under macroscopically elastic state, have revealed that the plastic stain is gradually generated after a certain number of cycles. Such mechanical property is often called as cyclic softening, and simulating the experimental evidence on the sudden generation of plastic strain under macroscopically elastic stress condition and followed fatigue crack initiation has been left as the challenging issues to be solved.
ABSTRACT: The paper discusses the experimental results for fluid structure interactions during the slamming impacts. This is a very challenging problem for the wave impacts on the bows or decks, where the slamming forces and hydro elasticity plays a major role in the ship design. Hence, in the present paper experiments were carried out for the hydrodynamic loads acting on rigid bodies striking a horizontal liquid surface at constant vertical speed. The study has been carried out by using a high speed hydraulic shock machine. Three different shapes of the rigid bodies, namely cones, square pyramid and Wedge-cone has been tested and the results shows that the deadrise angle has a high influence on the impact force. The values of slamming coefficient (Cs) have been obtained for all tested geometries. Their parabolic variations with the non-dimensional penetration have been confirmed by the experiments for the cones and the square pyramid. The three-dimensional effect has been shown with the impact of the wedge-cone. The variation of Cs was non linear compared to the standard linear response of the water entry for a wedge. Further, good agreement between theoretical models, numerical results and available experimental measurements has been obtained. INTRODUCTION The relative motions between the ships and the water can cause, in very large water impacts on the bows or the decks, severe damage to the ship. An improved understanding of these forces and the parameters involved in such slamming events can lead to better designs and to the development of improved simulation techniques for ship design. Recently the objective is to have larger and high speed vessels which impose a stern shape. This kind of hull form is more often susceptible to the slamming loads, so the structural design considering the slamming impact loads is more necessary.
ABSTRACT: In the UK, economic recession has placed pressure on financial, manpower and commodity resources targeted for Nuclear Decommissioning, leading to potential delay to elements of site remediation. Consequently, there are issues for both duty holders and regulators, as many assets on licensed sites will have to be safely managed for longer, to ensure continued control and containment of hazardous inventories. This Paper attempts to identify key elements, that need to be addressed in justifying future safety and creating a robust asset management regime; this includes whether the UK safety regulatory framework is flexible enough to accommodate future challenges. INTRODUCTION The UK is reaching a watershed in its nuclear programme. A new fleet of power reactors is presently being programmed, whilst many of the older MAGNOX reactors and radwaste legacy facilities have already entered IAEA ‘Stage 1’ Decommissioning. The effect of the world-wide recession has placed pressure on financial, manpower and commodity resources targeted for Nuclear Decommissioning, leading to potential delay for certain elements of Life Time Plans for site remediation. This Paper attempts to identify key elements that need to be addressed in justifying future safety and creating a robust asset management regime. Aspects such as the UK nuclear Regulatory Framework, the licensed Organisation, regulatory control through permissioning, good practice, asset management activities and regulation, storage of waste, provision of public information, asset management as part of the safety case, synergies with offshore rig situations and potential costs in delaying decommissioning are discussed and given fuller consideration in the Paper. UK NUCLEAR REGULATORY FRAMEWORK The main legislation governing the safety of nuclear installations in the UK is the Health and Safety at Work etc Act 1974 and the associated relevant statutory provisions of the Nuclear Installations Act 1965 (as amended).
- Energy > Power Industry > Utilities > Nuclear (1.00)
- Banking & Finance (1.00)
- Management (1.00)
- Health, Safety, Environment & Sustainability > Environment > Remediation and land reclamation (1.00)
- Health, Safety, Environment & Sustainability > Safety > Safety risk management (0.91)
- Health, Safety, Environment & Sustainability > HSSE & Social Responsibility Management > HSSE management systems (0.69)