A maneuvering simulation method is presented taking the roll coupling effect into account. Maneuverability of a Pure Car Carrier (PCC) is investigated by means of the simulation method. Using the PCC model, oblique towing and circular motion tests are conducted to capture the hydrodynamic forces acting on the model in heeled condition. The heel angle changes systematically from 0 to 15deg. Using the hydrodynamic forces obtained, turning simulations are made to capture the effects of ship approach speed.
RoRo is a vessel that can transport passengers, cargo, container and cars. Open Car Deck is favorite RoRo Vessel in developing countries due to its small GT, small tax and spacious car deck, but it has poor survival of stability. Many accident involve Open Car Deck RoRo which cause fatalities and victim. In order to ensure the safety of the ship, IMO had applied intact stability criteria IS Code 2008 which adapted from Rahola’s Research, but since 2008 IMO improved criteria become probabilistic damage stability SOLAS 2009. The RoRo type Open Car Deck has wide Breadth (B), small Draft (D) and small freeboard. It has difficulties to satisfy the ship’s stability criteria. Side Casings which has been applied in some RoRo have be known improve survival of intact stability and add small GT. In this paper investigated the effect side casings to survival of probabilistic damage stability. Calculation has been conducted for four ships without, existing and full side casings. The investigation results shows that defect stability of Open Deck RoRo can be solve with fitting side casing.
Department of Naval Architecture and Shipbuilding Engineering, ITS, Surabaya- Indonesia
Department of System Naval and Mechatronic Engineering, NCKU, Tainan-Taiwan
Indonesia Hydrodynamic Laboratory, IHL, Surabaya-Indonesia
There are several types of methods to calculate ultimate strength performance of stiffened panel structures such as experimental, numerical, and analytical method. This study proposes a design formula for predicting the ultimate strength performance of stiffened panel structures of ships. Basically, the empirical formula approach or design formula method is employed throughout the study. Results obtained from the above three methods is preferred in design code or guidelines. An average level of initial imperfection and 2 bay – 2 span (1/2 – 1 – 1/2) model is adopted in the proposed empirical formula. Effects of residual strength are not considered in this study. A total of 124 stiffened panels with four different plate slenderness ratios (
) and changing column slenderness ratio (
) are selected for simulation scenarios. The design formula is proposed based on results obtained by ANSYS nonlinear finite element analysis. The proposed method and details of the procedure are discussed.
Ocean and Ship Technology, Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, Perak, Malaysia
Graduate School of Engineering Mastership, Pohang University of Science and Technology, Pohang, Republic of Korea
Daewoo Institute of Construction Technology, Daewoo Engineering & Construction Ltd., Suwon, Republic of Korea
Steel Business Division, POSCO, Incheon, Republic of Korea
Northern Sumatera is subduction zone region which sustain a high magnitude earthquake. It caused Sumatera region encounter two plates, viz the Eurasian plate and the Indo-Australian. They are reinforced on active Semangko fault. Because of this both plates are convergent, and formed by subduction zone, it resulting in high earthquake frequency content. Then, it area traversed three faults: Fault Renun, Fault Toru and Fault Angkola through kilometer 475, which the source and the propagation of earthquake wave from Firma terrain. The impact of the earthquake at Northern Sumatera region is quite dangerous for local people. Besides that, the main factor of damages is depend on earthquakes magnitude acceleration. And then, from this value, will gain the earthquake intensity. On this case, we trying to manage the safety environment at this area using J48 desicion tree which aims to inform the most specific area experienced an earthquake. Based on the result of data processing, the largest earthquake area at Northern Sumatera is Nias region. It showed from the earthquake acceleration value between 202,71 – 542 gal, MMI scale > 7 SR and it has 1,5 latitude and 97,5 longitude. Then, the langkat Area, Deli Serdang and South Tapanuli include on moderate earthquake, because they have earthquake acceleration value range between 100 – 150 gal, and its MMI scale is ≤ 7.
Department of Physics, Faculty of Engineering, Mathematics and Natural Sciences, Indraprasta PGRI University, Indonesia
Informatics Engineering, Faculty of Engineering, Mathematics and Natural Sciences, Indraprasta PGRI University, Indonesia
In this study, the hydrodynamic performance of the H-type floating breakwater (H-Float) under regular wave action was assessed via large scale laboratory tests. Hydrodynamic performance indicators considered in this study are wave transmission coefficient CT and response amplitude operators (RAO) for heave, surge and pitch. The relations between the hydrodynamic performance indicators and the relative breakwater width for different breakwater draft ratios were ascertained through a series of systematic laboratory test program. The experimental results revealed that H-Float attenuated up to 80% of the incident waves. The relative breakwater width and the relative breakwater draft posed significant influences on motion responses of the test model. However, the motion responses were not much affected by the wave steepness.
Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia
In offshore industrial practice, prediction of wave kinematics above mean water level (MWL) by using linear random wave theory (LRWT) was led to unrealistic results due to high frequency of wave components. It is found to predict sensible kinematics below mean water level. Hence, to represent better and acceptable results above mean water level, empirical stretching methods in conjunction of LRWT (such as Wheeler and vertical stretching methods) have been used. However, the results of both have shown a very significant difference between one another and cannot be neglected where Wheeler stretching showed underestimate results of wave kinematics while vertical stretching overestimate the results. Since wave kinematics will be expressed directly in Morison’s equation for predicting the extreme responses (base shear and overturning moment) of an offshore structure design, it is important to minimize inaccurate results from the beginning of calculation steps in design process.
The modified form of linear random wave theory, effective node elevation and effective water depth procedures have been introduced as promising way to give better realistic presentations of near surface wave kinematics. There is some evidence from both studies that the wave kinematics results lay between the corresponding values of Wheeler and the vertical stretching methods. In this paper, the effects of different methods of simulating wave kinematics on the structural members (smooth and rough surfaces) are carried out lead to significantly different estimates of the 100-year responses.
UTM Razak School of Engineering and Advanced Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia
Tidal current energy conversion technology has been proposed by many researchers and companies as a solution for power generation with clean renewable energy resources. Until today, the technology is still at stage of research, development and field testing before it can reach a successful commercial stage. This study is conducted by reviewing published papers on tidal current turbines. Based on literature review, tidal current turbines can be classified into three types, horizontal-axis turbine, cross-flow turbine and vertical-axis turbine. Horizontal axis tidal current turbines have higher efficiency and have been developed by many renewable energy companies in the world. However, vertical axis tidal current turbines indicate opposite situations. The vertical type possesses some advantages that are cheaper in production, easier in installation because the generator can be placed on top, suitable for floating systems and others (Khan et al. 2009) and (Zeiner et al. 2015). It is applicable for some developing countries considering the capabilities of production technology and marine environment’s conditions. It becomes an appropriate solution in power generation, especially in developing countries. Therefore, the current study discusses about the advantages and the challenges that must be answered on vertical axis tidal current turbine development.
Department of Ocean Engineering, Faculty of Marine Technology, Institute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia
Department of Naval Architecture and Shipbuilding Engineering, Faculty of Marine Technology, Institute of Technology Sepuluh Nopember (ITS), Surabaya, Indonesia
Cost Recovery in upstream petroleum exploitation in Malaysia is a key motivator to international contractor. It is the most significant component of Production Sharing Contract. It represents a percentage of gross production once the discovered reserves go online. The processes of cost build up from sanctioned budget till incurrence is usually too delicate and subject to scrutiny. Question usually hangs in the mind that became an enigma is the possibility that the cost being inflated or justified. Approved cost inflated taken into Cost Recovery accounting will result in lesser profit oil or longer amortization period which will defer the benefit of Excess Cost Recovery to be shared. Studies on Cost Recovery usually dwell upon the cost only as a contractual item but none delve into the techno-commercial justifications as the cost builds up. This is the focus area of this paper. It began with the understanding of the approval process within Petronas. Then, the process emulated with the techno-commercial data acquired from completed projects where quite a number of possibilities of cost inflated enigma was unveiled.
UTM Razak, School of Engineering and Advanced Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia
Mooring line have several types of material which is chain, wire and synthetic fiber rope. Mostly, in oil and gas industry is use chain and wire rope as a mooring line for shallow water platform. When exploitation of oil and gas become deep, synthetic fiber is use as an alternative for mooring line. This paper focused on types of material and experimental by previous researcher for deep water mooring line. Besides that, the tensile test have been done for preliminary design stage. The test is to identify the material properties of mooring line. At this stage only focus on the steel wire rope with length 200mm and nominal diameter 2mm, 2.5mm, 6mm and 8mm. Finally, the conclusion and important summaries were presented according to the data collected.
Department of Aeronautical, Automotive and Ocean Engineering, University Teknologi Malaysia, Johor Bahru, Malaysia
In the wake of recent heightened interest in undersea exploration, the topics of Autonomous underwater vehicle (AUV) has become a recent trend in perspective of its versatile applications (e.g. pipeline inspection, underwater mapping and coral monitoring). Comparisons between numerical & empirical method is a standard exercise in terms of usability i.e. computational fluid dynamics (CFD) and International Towing Tank Conference method (ITTC), however majority of the work reported in the literature were only focused on the use of Myring Profile, rather than a free form method such as b-spline. In this work, comparison of results between calculations using empirical method and numerical method is presented, while utilizing b-splines representation to ensure free-form deformation capability. The comparisons conducted in this paper include the use of ITTC with form factor calculation to increase the accuracy of the preliminary estimates, where the numerical calculations were conducted using ANSYS software. Qualitative and quantitative observation concluded that the current model derived through the use of b-splines and Myring Profile resulted with models with small comparison error between classical ITTC method, ITTC with form factors and numerical method.
School of Ocean Engineering, Universiti Malaysia Terengganu, Terengganu, Malaysia