Naval Systems Research Articles

On the role of temperature in the response of air-backed composites to hydrodynamic loading: An experimental study

Understanding the role of temperature in the dynamic response of composite plates is critical for naval systems operating in extreme environments like the Arctic. Despite the advantages of composite materials in improving corrosion resistance and enabling the customization of material properties to their environment, their behavior at cold temperature, especially under dynamic loading, remains elusive. This research gap hinders the effective use of composite materials in extreme environments. Here, we study the dynamic response of air-backed fiberglass epoxy plates under hydrodynamic loading at room temperature and 4∘C. By employing digital image correlation and particle image velocimetry, we investigated the interplay between fluid–structure interactions and cold temperatures. Our findings reveal the critical role of temperature in shaping the dynamic response of air-backed composites through changes in the stiffness and damping properties. At cold temperature, the plate experiences a larger (smaller) deformation in the initial (latter) phase of the dynamic response. Furthermore, we observed a pronounced coupling between the structural response and the flow physics, with peaks of the hydrodynamic loading synchronized with the peak deflections. Our results underscore the importance of considering temperature in the design of naval systems for extreme environments, providing key insights into fluid–structure interactions at cold temperature.

Understanding the development of emerging complex intelligent systems

This paper explores the intricate emergence of complex and increasingly intelligent systems (CoIS) in the wake of new possibilities created by integrating artificial intelligence (AI) solutions, building on an analysis of the emergence of CoIS using perspectives of development and change. The findings, based on rich qualitative data collected through key informant interviews with reflective practitioners from aviation, automotive and naval system domains, indicate that firms facing the emergence of CoIS, need to build capabilities allowing several logics to co-exist in a newly evolving hybrid CoIS management logic.

Case Studies in Disaster: Modern Digital Engineering Methods and Error Detection

AbstractThe promise of Model Based Systems Engineering (MBSE) includes the ability to detect potential errors earlier and more accurately. This paper examines whether modern Digital Engineering (DE) techniques could have averted engineering disasters of the past had they been employed at the time. Three case studies are presented: Apollo XIII, Therac‐25, and a modern surface naval system. For each, the nature of the system and the error are discussed, and an abbreviated architectural model is presented, using a style designed for a semi‐automated model syntax analy‐sis technique called validation. A validation suite was executed against the example model to de‐termine if the defect which caused the failure was detected. Practitioners of systems engineering interested will benefit through these technical examples in leveraging MBSE for early develop‐ment defect reduction. Conclusions about which types of defects are detectable using modern MBSE techniques are presented with recommendations for future research.

The future of the European defense firm

The future European defense firm will be radically different, being determined by future threats, novel technology, and yet to come European defense policy. The immediate threat arises from the war in Ukraine, but longer-term European defense policy based on the Strategic Compass will provide the framework for the future European defense firm. Past developments offer some indication of the future and it is predicted that the defense firm has a future and will survive. The past trend of smaller numbers of larger defense firms will continue with firms being even more technologically-intensive—reflecting Augustine weapons systems, which are characterized by continuously rising unit costs and smaller volumes. There will be more mergers between European defense firms and more joint European projects developing and producing combat air and naval systems, tanks, and cyber systems.

Large eddy simulations of the turbulent channel flow over dimpled surfaces

Reducing skin friction has a key role in the efficiency of rail, highway, and airway transport vehicles or naval systems such as ships and underwater vehicles. In recent years, there is a growing interest in investigating turbulent drag-reducing capabilities of dimpled surfaces, which have great potential as a passive solution, while there still exists highly conflicting views and drag reduction rates reported in the literature as well as a lack of information about the drag reduction mechanism. In this study, large-eddy simulations (LES) were performed to investigate the characteristics and physical mechanism of the fluid flow over dimpled surfaces in a fully developed channel flow. The Reynolds number based on the channel height and the mean bulk velocity was nearly 5600 for all cases examined. Within the framework of the study, various dimple depth to diameter ratios as well as different dimple arrangements and geometries were considered. The detailed mean and instantaneous flow fields, turbulent kinetic energy budget and spectral characteristics of the flow are presented. The study revealed the potential of the dimpled surface in reducing skin friction and provided critical information about the flow features affecting the performance of the dimples.

Shallow-water waveguide acoustic analysis in a fluctuating environment.

The Acoustic Laboratory for Marine Applications (ALMA) is a deployable and autonomous acoustic system, designed by DGA Naval Systems, to address problems in underwater acoustics, such as sound propagation in fluctuating environments. In this article, data from the ALMA-2016 at-sea campaign are used to analyze the ocean fluctuation's influence on sound propagation in a shallow-water waveguide. The experiment took place on the continental shelf of the island of Corsica in November 2016. A source and a receiver array were 9.3 km apart in a nearly constant water depth of 100 m. The source emitted a variety of signals from which the chirp (1-13 kHz) is used to extract the waveguide eigenrays. To do so, a time-domain beamforming is performed on the match-filtered received signals with an automatic detection of local maxima in the time of arrival/direction of arrival (TOA/DOA) domain. A 2 min acquisition period of more than 13 h duration shows significant fluctuations in eigenray TOAs/DOAs. Qualitative comparisons with synthetic signals obtained from simulations in two and three dimensions permit reproduction of the observed eigenray fluctuations without including range dependence of the sound-speed profile.

Counteracting imagery (IMINT), optoelectronic (EOIMINT) and radar (SAR) intelligence

The development of military technique and technology forces necessary changes in military reconnaissance using advanced methods of contemporary battlefield imaging. This paper addresses the topic of imagery intelligence as an essential source for gaining information about the deployment and quantity of means and forces of a potential enemy. Currently, armies of the world are equipped with modern imagery intelligence systems that make it possible to collect, process and analyse the collected data on enemy’s troops and the environment in which the enemy operates. The purpose of the study is to present the proper role of camouflage undertakings that make it possible to counteract imagery, optoelectronic and radar intelligence. The increasing capabilities in this problem area mean that in the near future intelligence tasks will be carried out not only by ground, space or naval systems, but primarily by reconnaissance aircraft and unmanned aerial systems. In accordance with the problem indicated in the topic, the paper brings closer the possibilities of counteracting imagery intelligence from the theoretical and practical perspective. In addition, it presents the latest camouflage solutions employed both in the Polish Armed Forces and other selected armies. At the end of the paper, the authors formulate the most important conclusions that constitute a generalisation of the results of studies presented in different parts of the publication.

DRN-GAN: an integrated deep learning-based health degradation assessment model for naval propulsion system

PurposeThe purpose of this paper is to propose a new deep learning-based model to carry out better maintenance for naval propulsion system.Design/methodology/approachThis model is constructed by integrating different deep learning algorithms. The basic idea is to change the connection structure of the deep neural network by introducing a residual module, to limit the prediction output to a reasonable range. Then, connect the Deep Residual Network (DRN) with a Generative Adversarial Network (GAN), which helps achieve data expansion during the training process to improve the accuracy of the assessment model.FindingsStudy results show that the proposed model achieves a better prediction effect on the dataset. The average performance and accuracy of the proposed model outperform the traditional models and the basic deep learning models tested in the paper.Originality/valueThe proposed model proved to be better performed naval propulsion system maintenance than the traditional models and the basic deep learning models. Therefore, our model may provide better maintenance advice for the naval propulsion system and will lead to a more reliable environment for offshore operations.

Defence contractor adds desalination systems to is marine services

In the USA, Fairbanks Morse Defense (FMD), which builds, maintains and services naval power and propulsion systems, has acquired Maxim Watermakers, a privately-owned firm, based in Shreveport, Louisiana, that provides desalination and water treatment technologies for marine defence applications.

Experimental and numerical studies on the unsteady propeller thrust of underwater vehicles

ABSTRACT Experimental and numerical studies on the unsteady propeller thrust of underwater vehicles are presented. An experiment was conducted in a large cavitation tunnel at the Naval Systems Research Center in Tokyo, Japan. A large dynamometer was used to drive the propeller model, and an aft-body model, consisting of a stern-shaped tail and control surfaces, was fixed upstream of the propeller to simulate the wake of an underwater vehicle. The measured unsteady propeller thrusts were analyzed via a fast Fourier transform, and significant amplitudes were obtained at the blade-rate frequencies. The unsteady propeller thrusts were also examined using computational fluid dynamics under the experimental conditions. The numerical results agreed well with those of the experiment and provided insight into the propeller-thrust fluctuations in the wake.

Composite materials in ICTS-CEHIPAR

The Center for Hydrodynamic Research of El Pardo (ICTS-CEHIPAR) is a Unique Scientific and Technical Infrastructure (ICTS) part of the Deputy Directorate of Naval Systems (SGSN) of the National Institute of Aerospace Technique “Esteban Terradas” (INTA). A new research line to study the use of advanced composite materials in the naval industry has been recently opened in the Technology and Tests Department of ICTS-CEHIPAR. One of the main goals of this new research line is the monitoring of structural stresses in composite materials by means of fiber optical sensors in structural diffraction Fibers Bragg Gratings (FBGS). ICTS-CEHIPAR is enhancing the constructive procedures for the production of models of ships and naval devices made in composite materials. The implementation of instrumentation techniques for the monitoring of structural stresses in this kind of materials is necessary to detect possible damage due to different causes during the product lifetime. Results of scale model tests will be applied to the full scale ship construction and instrumentation methodologies, increasing ship safety and optimizing maintenance procedures.

INTERNATIONAL DEVELOPMENT AND VALIDATION OF A DISTRIBUTED SIMULATION FOR NAVAL SHIP REPLENISHMENT AT SEA

Navies from Canada, France, Germany, Italy, and the United Kingdom collaborated to develop and validate a distributed simulation of ship replenishment at sea. The simulation models the seaway, ship motions including hydrodynamic interaction effects between ships, and the transfer of a solid payload between ships using replenishment gear. The simulation was developed using the High Level Architecture (HLA), which facilitates sharing of data and synchronization of simulation time among software components on networked computers. Simulation results were validated using experimental data. The project demonstrated successful application of distributed simulation to complex naval platform systems. Lessons learned are shared for several areas, including seaway modelling, ship hydrodynamic interaction, and planning of model tests and sea trials for simulation validation.

Hydrodynamic Test Facilities in Naval Systems Research Center- Large Towing Tank, High Speed Towing Tank and Flow Noise Simulator

Hydrodynamic Test Facilities in Naval Systems Research Center- Large Towing Tank, High Speed Towing Tank and Flow Noise Simulator

A Triggering Mechanism for Cyber-Attacks in Naval Sensors and Systems.

In the maritime sector, the integration of radar systems, Automatic Identification System (AIS) and Electronic Chart Display and Information System (ECDIS) through digital technologies enables several benefits to maritime operations, but also make ships prone to cyberattacks. In this context, this work investigates the feasibility of an attacker using a radar system or AIS as open door to remotely send commands to a cyber threat hosted on a ship, even if the ship’s systems are air gapped—i.e., are not connected to other networks. The received commands are intended to trigger a cyber threat located in the ship. Although the literature covers several analyzes on cyber risks and vulnerabilities in naval systems, it lacks exploiting mechanisms capable of acknowledging attack commands received through radar and AIS. To this end, this work proposes a triggering mechanism that uses a template matching technique to detect specific patterns transmitted by the attacker to the ship’s radar or AIS. The results show the effectiveness of the proposed technique as a tool to acknowledge the received attack commands and activate a malicious code previously installed on the ship. In the case of attacks on a radar system, the accuracy achieved by the proposed method is 0.90. In the case of attacks on an AIS/ECDIS setup it presents an accuracy of 0.93. In both cases the proposed mechanism maintains the due safety against accidental attack activations.

함정 빅데이터 체계 구축을 위한 탑재장비 운용 데이터 수집 및 활용 방안 연구: 함정 전투체계 데이터 분석을 중심으로

함정 빅데이터 체계 구축을 위한 탑재장비 운용 데이터 수집 및 활용 방안 연구: 함정 전투체계 데이터 분석을 중심으로

Bidimensional Ray Tracing Model for the Underwater Noise Propagation Prediction

An increasing attention has recently been paid to the effect of the underwater noise field generated by ship activities on the marine environment. Although this problem is widely discussed in international treaties and conventions, it has not yet found a consolidated technical-scientific treatment capable of quantifying the level of underwater noise emissions produced by naval systems. As part of a national research collaboration, a novel code has been developed to predict noise propagation according to the Ray Tracing approach. Such optical geometry-based technique allows for calculating the Transmission Loss (TL) trend in its respective contributions: geometrical loss (due to the distance between the source and receiver), dissipation loss (due to the characteristics of the propagation environment), and reflection loss (due to the surfaces that delimit the field). The simulation requires as input parameters the source info as spatial position, frequency, and sound pressure level (SPL) as well as the sea properties like seabed depth, the speed of sound profile, the layers thickness the water column is divided into, the sea salinity, temperature, and pH. The simulation code provides the SPL spatial distribution useful as a fast industrial tool in the future studies addressed to identify the emission limits for the protection of marine wildlife.

The quest for and the implementation of new approaches to Russian naval system l administration in the context of the socio-political crisis during the 60-70s of the 19th century

The quest for and the implementation of new approaches to Russian naval system l administration in the context of the socio-political crisis during the 60-70s of the 19th century

19세기전반충청水營의 수군編制와 운영事例 - 『可考水營』을 중심으로-

19세기전반충청水營의 수군編制와 운영事例 - 『可考水營』을 중심으로-

해군 부대진단 제도의 적용과 발전방향에 대한 고찰

이 연구의 목적은 5년 동안 시행해 온 해군 부대진단 제도가 더욱 안정적으로 안착되기 위한 방안을 고찰하는 것이다. 해군의 부대진단의 역사적 과정, 이론적 배경을 확인하고 향후 방향을 조망함으로써 부대진단 연구의 성과를 확인해 보는 작 업이다. 그러므로 부대진단 제도의 중요성을 확인해 보는 동시에 어떻게 적용하였는지를 살펴보고 발전방향에 대해 설명하였 다. 특히 분석기법의 과학화, 분석프로그램 개발, 리더십 진단프로그램 개발, 부대진단 팀 인원강화, 전문성 및 신뢰성 확보 등 을 발전방향으로 제시하였다. 앞으로 해군의 부대진단 제도가 발전하기 위해서는 내ž외부적으로 지속적 연구가 필요하다고 판단된다.

Ordenanza de Matrícula para Cartagena de Indias (1777)

La presente transcripción corresponde a una copia de un reglamento cuyo original se encuentra en el Archivo General de Simancas, sobre el ordenamiento y función de la provincia marítima de Cartagena de Indias y la condición civil y militar de la gente de mar y maestranza dentro del sistema de reclutamiento naval llamado Matrícula de Mar en dicha provincia. El documento es rico sobre información relacionada con la producción de documentos, funciones burocráticas, competencias institucionales, actividades económicas y obligaciones de artesanos y pescadores que habitaban las costas del virreinato neogranadino a finales del siglo XVIII.