A REVIEW OF FORMULATIONS TO DESIGN AN ADHESIVE SINGLE-LAP JOINT FOR USE IN MARINE APPLICATIONS

The single adhesive joint has many applications in the shipbuilding industry, where it offers the advantage of joining materials (adherents) with different properties and characteristics using an adhesive. However, one disadvantage of this type of joint is the stress concentration at the ends of the joint, which directly affect the adhesive. Another disadvantage is the possible difference between the coefficients of thermal expansion of the adherents of the joint. Through compilation and classification of the formulas found in various publications, this study presents a state-of-the-art review of an adhesive single-lap joint that can be used in marine applications. It will consider the types of materials used as the adhesive and as the adherents, the possibility of varying the thicknesses of the adherents and the thickness of the adhesive, and the recommended design factors for each proposed methodology. This study proposes formulas to estimate the stresses for joints with balanced thicknesses and extrapolates the results for non-balanced joints; also, an equation is derived to calculate the minimum overlap joint length for ship lengthening, allowing the design process to be simplified. The results are expected to facilitate the design of single-lap joints in marine applications, such as reinforcing composite panels and lengthening of hulls and superstructures

A REVIEW OF SHIP MOORING SYSTEMS

The physical principle that governs how ships are moored to a port has changed little over the years. Nevertheless, in recent decades, there have been developments in maritime transport towards increased vessel dimensions and operations in specialist terminals. These trends mean that offshore ports and mooring systems have to face more challenging conditions in terms of the waves, wind and drift current. At the same time, pier side port loading and unloading systems place demands on the mooring system, which must immobilise ships better. In this situation, the mooring system’s own equipment, such as lines, deck fittings and mooring winches, must also evolve to work alongside new port devices. It is also necessary to point out that changes in mooring will take place in subsequent years. These innovations in attaching the ship to the pier will be highlighted here as they mark a significant change in mooring and pier components

A REVIEW OF THE DRIVE OPTIONS FOR OFFSHORE ANCHOR HANDLING WINCHES

This article discusses the state of the art for driving technologies of anchor handling winches for offshore operations. These systems are necessary for anchor handling operations associated with installation of many types of moored floating offshore structures. To perform these operations, it is necessary to use specialized vessels known as AHT (Anchor Handling Tug) or AHTS (Anchor Handling Tug Supply) vessel, which incorporate specific equipment such as towing winches, but with higher performance than conventional tugs both in size and in technical performance. There are nowadays two main options for driving the Anchor Handling/Towing winches: hydraulic with low or high pressure motors, and electrical with AC motors driven by Variable Frequency Drives. Additionally, a new technology is appearing in the industrial sector which is starting to be applied in the marine sector, and in some cases for anchor handing winches: the permanent magnet motor. The aim of this paper is to discuss these driving technologies and their importance in the future of this part of the marine sector

A Review of Formulations to Design an Adhesive Single Lap-Joint for Use in Marine Applications

[Abstract] The single adhesive joint has many applications in the shipbuilding industry, where it offers the advantage of joining materials (adherents) with different properties and characteristics using an adhesive. However, one disadvantage of this type of joint is the stress concentration at the ends of the joint, which directly affect the adhesive. Another disadvantage is the possible difference between the coefficients of thermal expansion of the adherents of the joint. Through compilation and classification of the formulas found in various publications, this study presents a state-of-the-art review of an adhesive single-lap joint that can be used in marine applications. It will consider the types of materials used as the adhesive and as the adherents, the possibility of varying the thicknesses of the adherents and the thickness of the adhesive, and the recommended design factors for each proposed methodology. This study proposes formulas to estimate the stresses for joints with balanced thicknesses and extrapolates the results for non-balanced joints; also, an equation is derived to calculate the minimum overlap joint length for ship lengthening, allowing the design process to be simplified. The results are expected to facilitate the design of single-lap joints in marine applications, such as reinforcing composite panels and lengthening of hulls and superstructures

Algunas plantas de interés de la Sierra de Aguafría (Monesterio, Badajoz)

Se comentan once taxones de plantas vasculares presentes en la Sierra de Aguafría (Sierra Morena occidental, sur de la provincia de Badajoz), de valor corológico por tratarse de especies nuevas, raras o poco conocidas para la provincia o Sierra Morena. Se trata de Armeria capitella Pau, Erica lusitanica Rudolphi, Eupatorium cannabinum L. subsp. cannabinum, Genista falcata Brot., Halimium halimifolium (L.) Willk. subsp. halimifolium, Molinia caerulea subsp. arundinacea (Schrank) H. K. G. Paul, Osmunda regalis L., Osyris lanceolata Hochst. & Steud., Prunus cerasus L., Quercus pyrenaica Willd. y Sibthorpia europaea L. Para cada uno de ellos se aportan datos ecológicos, así como referencias previas sobre su distribución en la región.his work analyses eleven taxa of vascular plants located in the Sierra de Aguafría (Western Sierra Morena, Southern Badajoz Province) that are new or almost unknown for the region: Armeria capitella Pau, Erica lusitanica Rudolphi, Eupatorium cannabinum L. subsp. cannabinum, Genista falcata Brot., Halimium halimifolium (L.) Willk. subsp. halimifolium, Molinia caerulea subsp. arundinacea (Schrank) H. K. G. Paul, Osmunda regalis L., Osyris lanceolata Hochst. & Steud., Prunus cerasus L., Quercus pyrenaicaWilld. and Sibthorpia europaea L. We include ecological data for each species and references about their distribution throughout the region

Precautions to Consider Working with Mooring Capstans and Winches

[Resumo] Na actualidade prodúcense moitos accidentes durante as operacións de amarre dos buques. O deseño das máquinas e os cabrestantes de amarre xoga un papel importante á hora de reducilos. Adicionalmente, a situación do persoal sobre as cubertas dos buques é outro factor que axudará á redución dos accidentes acontecidos a bordo.[Abstract] In recent years, many accidents are occurring during mooring operations of vessels. The capstan and winches design and the crew situation on the deck of ships are two factors that may reduce the number of accidents inboard

ESTUDIO COMPARATIVO PARA LA SELECCIÓN DEL EQUIPO DE AMARRE EN UN BUQUE TIPO REMOLCADOR Y EN UN BUQUE DE GUERRA

Classification Societies (SC) of ships listed in different chapters of the regulations, recommendations and requirements for the selection of mooring equipment on ships regarding quantification for each type of ship, the analysis of the materials used and tests to suffer the various elements of mooring equipment. This article relates to how it affects the implementation of the different regulations of the SC when providing a tugboat and a military vessel from its mooring and anchoring systems. The research results are obtained by performing a comparison between the demands imposed by the SC to civilian ships and warships

Definition of an Artificial Reef Unit through Hydrodynamic and Structural (CFD and FEM) Models—Application to the Ares-Betanzos Estuary

[Abstract] The application of hydrodynamics to the definition of artificial reefs is of great interest since the positioning of the artificial reef modules on the sea floor alters the water velocity field, causing an appropriate circulation of nutrients and promoting a habitat for settling desired species. Nevertheless, the designs must be subjected to a structural calculation that will condition the constructive process to be applied. The present research proposes a methodology to determine the geometry of an artificial reef in terms of hydrodynamic and structural criteria. The solution proposed was analyzed through Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM). Using concrete as base material for artificial reefs, four different dosages were proposed with different proportions of cement and water, leading to different mechanical properties, which determine different constructive strategies, such as dwell time in the mold. From the hydrodynamic point of view, it was found that the solution proposed provides a proper replacement of nutrients. From the structural point of view, it was found that the solution proposed does not need steel reinforcements in concrete, which improves the sustainability of the artificial reef. The four different concrete dosages will condition the constructive strategy through the dwelling time in the mold and, for any established production, the necessary number of molds (formworks).Xunta de Galicia; CN-10MMA003C