Naval Design Research Articles

15 PhD positions in GRAPES

We are pleased to announce 15 open PhD Positions within the new European Network GRAPES: Learning, Processing and Optimising Shapes. GRAPES is a Marie Sk lodowska-Curie Innovative Training Network in the framework of H2020, started on December 1st, 2019, and lasting for 4 years. It includes 11 academic/industrial groups o.ering 15 PhD's, and 6 associated partners; it is coordinated by ATHENA Research & Innovation Center, Greece. GRAPES aims at advancing the state-of-the-art in Mathematics, Computer-Aided Design, and Machine Learning, in order to promote game changing approaches for generating, optimising, and learning 3D shapes, along with a multisectoral training for young researchers, supported by the active participation of SMEs. Recent advances in the above domains have solved numerous tasks concerning multimedia and 2D data. However, automation of 3D geometry processing and analysis lags severely behind, despite their importance in science, technology and everyday life, and some well-understood underlying mathematical principles. Concrete applications include simulation, manufacturing and 3D printing, visualisation and naval design, retrieval and mining, reconstruction and urban planning.

A Framework for Integrating Human Factors in the Early Stages of Ship Design: Application to the Mess Halls of a Surface Combatant

The new F-110 frigates project is currently in the conceptual design and definition phase. General arrangement has to be defined; there are many demands and proposals of changes. One of them is the design of the most crowded areas, the mess halls. The aim of this article is to provide the Spanish Navy Staff with a decision tool that helps in determining the optimal distribution of the future F-110 mess halls. For this purpose, a new "analytical decision maker" model was designed providing advanced statistical methods and computer pedestrian simulations within multicriteria decision-making framework that allows optimizing conceptual designs. To reduce subjectivity, crew movement simulations and statistical methods were added to the multicriteria decision model, thus creating a less-subjective decision tool. A sensitivity analysis was conducted to check the robustness of results. An integrative decision and design approach are necessary for broad acceptance of human factors adoption within naval architecture design. 1. Introduction 1.1. Ship design and human factors Ship design is a complex challenging process that requires the successful coordination of many different disciplines and that necessarily involves trade-offs between competing interests to achieve a balanced result. Hence, ship designers need to understand the complex interaction between different design drivers and their influence on the final solution, always being aware that the cost of rework may become drastically high if errors are found in the later stages of the design.

Hybridization of the imperialist competitive algorithm and local search with application to ship design optimization

In the wide scenario of the optimization techniques, a large number of algorithms are inspired by natural processes, in many different ways. One of the latest is the Imperialist Competitive Algorithm (ICA) Atashpaz-Gargari and Lucas (2007), judged by their authors as very efficient and competitive with other popular optimization algorithms. However, its diffusion is still limited, so that it has not yet been adequately studied.In this paper, we have investigated the convergence properties of the ICA algorithm, observing the effect of the various coefficients and their role in the global convergence. Some modifications, including the coupling with a local search method, have been listed/suggested and then tested on a suite of standard algebraic test functions, verifying the improvements on the speed of convergence of the original algorithm. An application to naval design has been also included, in order to check the ability to solve realistic problems.

Theoretical and experimental study of underwater explosion performance of selected explosive compositions

Measurements of underwater explosion parameters and their effects are still the major problem for naval designer. In this study, thermo-chemical calculations have been carried out using EXPLO5 code to determine the underwater explosion parameters for different selected explosive mixtures. Preparation of the different types of explosive mixtures based on melt cast explosive (TNT) and plastic bonded explosives (PBXs) based on polyurethane binder system were presented. The effect of different aluminum weight percentage for the selected explosive mixture has been investigated with respect to the impulse and the resulted deformation. Underwater experimental measurements of the prepared explosive mixtures based on steel plate’s deformation were determined and compared. It was concluded that PBX based on RDX in addition to 25 wt% aluminum and 30wt% ammonium perchlorate produces the highest underwater explosion performance from all the tested samples. This explosive mixture is candidate to replace the traditional well known TNT in the underwater explosive applications.

Validation of potential flow method for ship resistance prediction

Considering the extensive use of numerical methods in naval design, a question about the accuracy numerical tools that could estimate the flow around the ship and which are the limitations of these tools for practical design applications. In this context, experimental test on scaled models play an important role in validation of numerical simulations. This work is dedicated to validation of the method used to calculate the non-linear potential free-surface flow around the ship. Global quantities, as total resistance, wave resistance coefficient, residual resistance coefficient are flow characteristics concentrated in a single value, and their validation provides a criterion for choosing the optimum hull. Validation of physical phenomena is done using the wave profile, the pressure distribution on the body or the free surface topology. Validations were developed by comparing experimental data published for benchmark test cases, results of the resistance test performed in ICEPRONAV towing tank, against the results of numerical calculation performed by the author. Numerical simulations were performed using the XPAN module of the SHIPFLOW program, dedicated to the calculation of non-linear potential free-surface flow. Therefore, in order that the validation to be consistent and not influenced by scale effects, all calculations have been performed for the model scale. For this purpose, numerical studies have been considered for three ship models with different complex geometries. Two of the three hulls, the 60 Series and the DTMB 5415, are benchmark tests, chosen due to a wide range of detailed experimental and numerical results. The other one is case study for which experimental measurements were carried out in the frame of research projects.

Multi-Role Vessels: Design, Manning & Cost Drivers

Informed by the Naval Design Partnering involvement in concept design for future UK warships and auxiliary vessels, this paper comments on the technological developments supporting the emergence of multi-role vessels in modern navies, including both manpower considerations and what modularity or flexibility means for the future cost-capability trade space for naval design. It refers to the future trends in naval surface ship designs and technologies, including expected trends in autonomy and unmanned systems. It challenges traditional views on deploying capability, considers the design and cost drivers for multi-role vessels and explores what this might mean in terms of how complexity impacts ship size and cost. A key consideration is how well the different roles can co-exist in one vessel, with examples given of different roles that would dovetail together well to address the concurrency requirement of different capabilities in a single ship. The paper reflects on the significance of naval manpower as the key through life cost driver for naval programmes, and the implications for the manning solutions and cost of future multi-role ship concepts.

Standardisation of Naval Containerised Modules - Enabling Interoperability Across NATO

This paper explores the work carried out by the Naval Design Partnering (NDP) team to propose a new North Atlantic Treaty Organisation (NATO) standard covering naval containerised modules outfitted with mission systems. The purpose of the Standard is to facilitate interoperability of naval modules across NATO navies, and to future proof the design process both for supply-chain and vessel designers. Drawing upon the experience of the offshore world in using containerised modules, as embodied in the current certification standards, the Standard provides a uniform set of safety-related construction requirements, standardised interfaces, and guidance for platforms to enable the deployment of naval modules. The paper covers the overall philosophy behind the Standard, the background research conducted, and the rationale behind the requirements chosen. Finally, it explores the impact of the Standard on platform design, the key enablers for the deployment of naval modules, and the future work to develop international inter-operability.

A Spatial Layout Optimization Program Considering the Survivability of a Naval Vessel in the Early Design Stage

As mission capability and scope of naval vessels are increasing, there has been an emphasis on the importance of survivability of naval vessels. Elements of survivability include susceptibility, vulnerability, and recoverability among which vulnerability is directly associated with the interior spatial layout of a naval vessel. However, various other elements also must be simultaneously considered in the design phase of a naval vessel. Accordingly, this study proposes a method that considers survivability an assessment factor by quantifying vulnerability in attacks, which is directly associated with the effect of spatial layout of a naval vessel. Furthermore, to automatically create spatial layout alternatives of naval vessels and efficiently deduce optimum spatial layout results, this study developed an optimization program for the spatial layout of naval vessels. The differential evolution algorithm was used for the optimization, and its effectiveness was validated by applying it to various examples. 1. Introduction The spatial layout problem, arranging equipment and facilities that perform various functions in a limited space, requires various layout alternatives to reflect the intention of the designer. The problem of arranging equipment and compartments in a vessel can also be regarded as spatial layout problem. In particular, spatial layout of a naval vessel must consider the characteristics of the naval vessel, which performs multiple tasks such as battle, habitation, maintenance, and communication to establish systematic spatial layout strategies. Many studies have been conducted regarding ways to perform spatial layout in light of various elements from the initial design phase of naval vessels. The intelligent ship arrangement (ISA) algorithm has been proposed by the University of Michigan research team in the United States (Parsons et al. 2008). The University College London (UCL) research team in the UK also proposed a ship design method using the design building block concept (Andrews 1998), and then extended their research to apply the simulation-based design concept (Andrews 2006). In the Netherlands, the TU Delft research team suggested a method of applying the packing approach to the initial design stage of the vessel (van Oers & Hopman 2010; van Oers 2011). Especially, the UCL research team developed the naval vessel design module SURFCON, which is applicable to the PARAMARINE ship design software. In Korea, regulations and the system for designing naval vessels and spatial layout are defined, but there are no processes or specific methodologies to apply them to the actual naval vessel design process. Therefore, spatial layout of naval vessels is being carried out based on the experience and subjective judgment of experts.

A framework to improve the naval survivability design process based on the vulnerability of a platform's systems

Offshore Patrol Vessels (OPVs) are a relatively small type of vessel designed for quick naval defence response in littoral zone. OPVs also have a complex system layout, because they are constructed to include both commercial and naval aspects with functionality to facilitate its operational defence duties and capability. Furthermore, this complex system layout may not be optimised for survivability. This study presents a novel framework to examine survivability related system and functional dependencies of an actual OPV, combining different modelling techniques. The OPV is modelled and analysed using a physics-based vulnerability assessment model and integrated into a dynamic system supply and demand model. The output is then analysed through a machine learning algorithm to identify functional relationships between systems and the vessel's operational capabilities to then build a Bayesian Network for further analysis. The Bayesian Network model is used to identify single point failures and analyse the OPV's equipment/on-board systems for sensitivity to the survivability of the platform. The results demonstrate the ability of the machine learning algorithm to build a Bayesian Network that can effectively improve the naval design process and subsequently contribute to enhancing the survivability of OPVs.

A compared study of the shape’s plate behaviour under the impact load

A major stage in the naval design is to establish the structural resistance of the ship body. Non-linear FE analysis methods are used for determination the hull’s structural capacity. The plates and the beams are important constructive elements of the ship structure. This paper presents a compared study of the impact analysis of the plates with different curvature. Both non-linear static and dynamic analysis are made to understand the structural behaviours of the plates. It deals with determining the deformations and stresses obtained from implicit static and explicit dynamic analysis. In order to evaluate the influence of shape plate on structural behaviour, the energy dissipation is observed by calculating the absorbed energy. The main results will be used in the process of optimisation the ship body’s shell shape.

Prediction of Topside Electromagnetic Compatibility in Concept-Phase Ship Design

An approach for the prediction of topside electromagnetic compatibility in the concept phase of naval ship design is proposed and demonstrated. The approach was developed by utilizing the commercially available numerical computational package, Computer Simulation Technology, to assess the electromagnetic environment of a Royal Navy Type 22 Batch II Frigate. A number of the results of such an assessment were validated using measurements on a 1:50 scale copper model of the Type 22 Batch II Frigate. The approach was then applied to a new concept phase design study for a Future Patrol Ship, produced by UK Ministry of Defence's Naval Design Partnership. This work is expected to be useful in assessing the severity of topside EMI, using numerical modeling and simulations, in Concept-Phase Ship Design.

Split TSHD hydrostatic particulars calculation for cargo discharge phase using polynomial RBF

Split Trailing Suction Hopper Dredgers (TSHD) are special type of working ships, whose hulls open to discharge cargo to certain unloading positions while being at sea. Although they have variable hull geometry, their hydrostatic and stability characteristics are usually calculated for unchanged initial hull geometry loading conditions only, and such calculations are supported by classification society stability regulations for that ship type. Nevertheless, in this study, we show that hydrostatic particulars for intermediate loading conditions of variable ship geometry can be calculated by using analytical solutions of basic hydrostatic integrals for arbitrary list angles, obtained for polynomial radial basis function description of ship geometry. The calculations will be performed for symmetric hopper opening during cargo discharge procedure, thus covering all Split TSHD regular unloading conditions, without examination of ship hull opening failure modes. Thus, all ship hydrostatic properties will be pre-calculated analytically and prepared for further stability calculations, as opposed to the usual numerical calculations for initial geometry and even keel only, as currently used in naval architecture design.

Development and Application of an Incompressible Strand Solver

Computational fluid dynamics (CFD) is an ever-increasing component of the naval design and analysis process. Most current high-fidelity CFD methods used by the US Navy require body-fitted volume grids, which are time-consuming and depend on seasoned engineers with significant grid generation experience. Automated grid generation using a strand gridding approach is a relatively new concept that could transform the role of higher fidelity CFD within the Navy's design and analysis process. The HPCMP CREATE-SH team seeks to expand the compressible strand solver under development as part of the HPCMP CREATE-AV effort to incompressible flow problems for applications of interest to the Navy. The completed incompressible strand solver would allow quicker turnaround time for experienced CFD engineers while allowing more naval architects to use higher fidelity CFD as a part of the overall design process. The incompressible strand solver is a new development of the HPCMP CREATE-SH Hydro team, and this work will demonstrate the solver on validation cases of naval interest.

Safe Lithium-Ion Batteries? Predicting Performance over a Range of Operating Conditions

Electrochemical-thermal coupled modelling of lithium-ion batteries is used to simulate battery performance. Modelling can be used to investigate the effects of different materials and design parameters on battery performance and safety. Numerous models exist for lithium-ion batteries1 from microscopic through to module scale simulations. Majority of these models simulate cell performance under normal charge and discharge operation. Generally these models do not accurately predict cell behaviour outside of normal conditions, such as at high temperatures. Operating lithium-ion cells at high temperatures can lead to an internal thermal event and ultimately cell failure. A number of models have been developed to simulate cell behaviour outside normal conditions however these models do not include the performance of cells during normal operation. A model that simulates cell performance over a range of conditions is necessary to make an informed decision regarding material and design changes. This work aims to combine two existing models to create a new model for simulation of cell performance under normal and high temperature conditions. Two existing models were chosen to create the new model. The models were selected to meet the following criteria: 1) single cell model 2) stacked plate configuration 3) individual component layers modelled (no homogeneous core assumption) 4) includes temperature dependent material properties (or able to be included). The first is a 1D electrochemical-thermal reduced order model developed by Gambhire et al.2 for simulation under normal charge and discharge operation. The second is a 1D electrochemical-thermal coupled model developed by Wang et al.3 for simulating internal thermal events including decomposition reactions for each cell component. Key aspects of both models have been used to create a new model implemented in COMSOL Multiphysics®. The new model is expected to more accurately describe cell behaviour over a range of conditions. The results of this study will be presented at the conference. Acknowledgments: The authors acknowledge the funding support provided by the ARC Research Training Centre for Naval Design and Manufacturing, PMB Defence Engineering, and the CSIRO Manufacturing High Performance Metal Industries Program.

Acoustic radiation from an infinite submerged, line-driven plate with attached finite plate

The structural acoustics and vibration related to submerged, structurally driven elastic plates is germane to a wide range of applications in U.S. Navy undersea vehicle and system designs. Of particular interest to a recent specific Naval design application was the examination of effects on the acoustic radiation from a very large, fluid-loaded elastic plate joined with a “welded,” or strongly attached, smaller elastic plate subjected to force-loading excitation somewhere on the large plate. This paper presents the results following an examination of several theoretical approaches to predicting the radiated sound level (both levels and directivity) of an idealized infinite plate and perfectly attached thin, finite plate submerged in a heavy fluid and driven by a line-load at varying locations on the infinite plate. Parametric studies are also presented to both highlight the underlying basic physical mechanisms and also to investigate the effect on sound radiation of varying system parameters. Specifically, results of parametric variations in (a) location of the line force on the plate with respect to the attached finite plate, (b) length/size of the attached plate, (c) mass and/or stiffness of the attached plate, (d) frequency of the harmonic line-load, and, time permitting, and (e) the mechanical theory of the attached thin plate, are all presented herein.

Design for flexibility: Evaluating the option to extend service life in preliminary structural design

In this paper, a new type of real options analysis is used to evaluate the worth of an option to extend the service life (ESL options) of an aluminum structure from twenty to twenty-five years. It is an early application of prospect theory-based real options analysis (PB-ROA) in naval design. PB-ROA abstracts the principles of real options analysis to suit naval design applications where the assets do not generate cash flows, and therefor one cannot define value in monetary terms. Instead, the example in this paper defines the utility of a structural design based on three components: structural availability, cargo capacity, and producibility. The utility is contingent on risk factors like the time to crack initiation of a welding detail which is included using stochastic fatigue analysis. From an entire Pareto front of optimal structural designs, the options analysis exposes a partition in the design space which could be valuable in a design setting. The partitioning reveals the conditions in which certain candidate designs maximize the present value of future flexibility. Ultimately, this paper demonstrates a new approach to valuing flexibility in preliminary structural design that may generate useful insight for early stage decision makers.

Review of Global Naval Shipbuilding Trends and Lessons for Indian Shipbuilding Industry

It is estimated that over the next two to three decades, the global naval shipbuilding industry could see an investment of over US $835 billion in new warship and submarine construction. In an ambitious effort, many countries are now analysing the strengths and weaknesses of their respective naval shipbuilding industries in order to renew their naval fleets. Towards this end, specialist studies and research have been commissioned by various stakeholders, to take a strategic look at the shipbuilding industry to determine lessons from some recent naval construction programmes, identify capacity limitations (in terms of infrastructure, skills and character of the workforce, and suppliers who constitute the ecosystem) and explore policy options that are open to the government and the industry to overcome any limitations. This paper presents a review of a few of these studies and identifies the factors that are likely to impact on future naval construction and acquisitions. The paper also examines trends in naval design and construction technologies and presents possible lessons for the Indian naval shipbuilding industry.

Comparing Trimaran Small Waterplane Area Center Hull (TriSWACH), Monohull, and Trimaran Hullforms: Some Initial Results

Alternative hullforms such as multihulls may allow small vessels to deliver levels of performance normally associated with a far larger and more costly monohull vessel. This article describes a research program on alternative hullforms being undertaken by a consortium of six universities and academic institutions. As well as reviewing the current research program, this article discusses in detail the contribution being made by University College London (UCL): tools for undertaking the comparison and exploration of the monohull, trimaran, and Trimaran Small Waterplane Area Center Hull (TriSWACH) alternatives. These tools combine the modeling and analysis capabilities of an existing naval architecture design package with a varied range of search and optimization techniques to enable the exploration of alternative ship design solutions. This article presents the initial results obtained from tools that are currently under development at UCL. Such tools can be applied to identify and explore key topics related to the trimaran and TriSWACH hullforms when compared with a baseline mono hull configuration. The trimaran hullform has significant potential for small fast combatants as demonstrated by the U.S. Navy's LCS program. The TriSWACH hullform (with a small waterplane area center hull stabilized by two outriggers) is of interest because it offers the potential for improved seakeeping performance.

Comparing Trimaran Small Waterplane Area Center Hull (TriSWACH), Monohull, and Trimaran Hullforms: Some Initial Results

Alternative hullforms such as multihulls may allow small vessels to deliver levels of performance normally associated with a far larger and more costly monohull vessel. This article describes a research program on alternative hullforms being undertaken by a consortium of six universities and academic institutions. As well as reviewing the current research program, this article discusses in detail the contribution being made by University College London (UCL): tools for undertaking the comparison and exploration of the monohull, trimaran, and Trimaran Small Waterplane Area Center Hull (TriSWACH) alternatives. These tools combine the modeling and analysis capabilities of an existing naval architecture design package with a varied range of search and optimization techniques to enable the exploration of alternative ship design solutions. This article presents the initial results obtained from tools that are currently under development at UCL. Such tools can be applied to identify and explore key topics related to the trimaran and TriSWACH hullforms when compared with a baseline monohull configuration. The trimaran hullform has significant potential for small fast combatants as demonstrated by the U.S. Navy's LCS program. The TriSWACH hullform (with a small waterplane area centerhull stabilized by two outriggers) is of interest because it offers the potential for improved seakeeping performance.

Microscopic Approach to Evaluate Energy Consumption and Emissions from Ships

Maritime transport plays a central role in the debate about the sustainability of the transport sector. Analyses suggest that air emissions from shipping account for a significant portion of total emissions, affect air quality, and contribute to climate change and human health problems. The existing trend suggests that the situation will worsen. These results, though affected by obvious uncertainties, highlight the urgent need to take action. Harmful environmental impacts are controlled primarily through legislation prohibiting the use of certain substances, setting limits on emissions, and enforcing certain technical standards. However, the basis for designing effective policy instruments to abate air emissions is finding reliable estimates of those emissions. For the shipping sector, a debate continues about the most appropriate way to achieve its air emissions estimate. This paper contributes to this debate by proposing a new methodology that applies some of the available theories from the naval design scientific field to derive a microscopic analytical formulation of the energy produced and consumed by a ship during its trips. The methodology proposed is applied to evaluations of potential savings in energy and emissions by adjusting the speed–acceleration profile of ships in port. Results achieved confirm the power of the methodology and open its application to other case studies. They also highlight an aspect usually neglected in the literature: the impact of ships' activities in port on the environment. The simple exercises performed show clearly the relevance of the issue. They are also able to show that better management of ships' movements in port may produce significant environmental benefits.