Hatch Covers Research Articles

Determining the influence of sandwich-type components on the load of a hatch cover in a universal open wagon

The object of the study reported here is the processes of occurrence, perception, and redistribution of loads in the improved structure of the hatch cover in a universal open wagon. In order to reduce the load on the cover of an open wagon hatch, and, accordingly, to improve its strength, it is proposed to improve its design by introducing sandwich components. The thickness of the sheets that form the hatch cover has been determined. The dynamic loading of the hatch cover in the vertical plane was studied. It was found that the accelerations acting on the hatch cover with the proposed improvement are almost 20 % lower than those acting on the typical structure. The basic strength indicators of the hatch cover under the operational modes of its load have been determined. The results of the calculation showed that the maximum stresses in the hatch cover are 22 % lower than permissible ones. In addition, within the framework of the study, the main indicators of the dynamics of the open wagon equipped with the proposed structure of hatch covers were determined. The movement of the open wagon under the condition of movement in an empty state is rated as "good". At the same time, the maximum accelerations in the center of mass of the supporting structure of an open wagon were 4.6 m/s2, and the coefficient of vertical dynamics was about 0.6. Special features of the results within the framework of this study are that the proposed improvement of the hatch cover helps improve its strength by reducing the dynamic load, and not by strengthening the structure. The scope of practical application of the results is the engineering industry, in particular, railroad transport. The conditions for the practical use of the research results are the use of energy-absorbing material in the sandwich-type components that form the hatch cover. The study reported here could contribute to devising recommendations for the construction of components in the structures of modern freight cars, thereby reducing the costs of maintaining them in operation, as well as increasing the profitability of railroad transportation

Development of the IACS Unified Strength Requirements for Hatch Covers—UR S21

International Association of Classification Societies (IACS) is responsible for many of the ship strengthrules including both generally applicable Unified Strength Requirements (UR-S) and other rules specific for various ship types. For historical reasons, there have been different structural strength requirements regarding hatch covers, hatch coamings, and related structures in IACS UR S21, S21A, and CSR (Common Structural Rules for bulk carriers and oil tankers). This paper presents the work carried out to improve the related rules and thereby the development of the unified strength requirements for hatch covers. Firstly, related IACS rules are reviewed and compared, and some major improvements to the buckling formulations are proposed for improved accuracy. Secondly, with UR S35 being developed as a unified buckling toolbox, the unified strength requirements for hatch covers—UR S21 (Rev.6, complete revision)—are developed with a standardized interface of reference to UR S35 for buckling assessment. Finally, the numerical calculations of typical stiffened panels and full hatch covers are carried out for rule verification and consequence assessment, which demonstrates that more rational hatch cover designs can be achieved based on UR S21 (rev 6).

An integrated group entropy-weighted interval type-2 fuzzy weighted aggregated sum product assessment (WASPAS) method in maritime transportation

This study aims to provide an integrated decision-making approach in maritime transportation problems. The duty of hatch cover is to prevent the ingress of water into the cargo hold and protect the goods from being damped and damaged. Hence, it has the considerable role in productivity of maritime transportation systems. Since each hatch cover has distinguished properties with respect to criteria than the others, the hatch cover selection problem (HCSP) can be considered as a multi-criteria decision-making (MCDM) problem. In this paper, interval type-2 fuzzy sets (IT2FSs) are first used to weight criteria and evaluations of hatch covers with respect to criteria. In addition, an integrated group Shannon entropy- based weighted aggregated sum product assessment (WASPAS) approach is applied to solve the HCSP using the limit distance mean (LDM) in which the interval type-2 fuzzy Shannon entropy approach is used to determine the objective weights and then they are integrated with the subjective weights. On the other hand, in order to demonstrate the effectiveness and practicability of the proposed method, it is fulfilled in a real case study and the ranked results are compared with the others.

Marine hatch covers using light-weight GFRP composites: Experiments and finite element simulations

In this paper, Finite Element Analysis was used to simulate ship hatch covers with different grid geometries viz. Square grid, Inclined grid, Diamond grid and Honeycomb grid. The entire finite element analysis results were generated by ANSYS® 2022 workbench environment. The hatch cover provides an air tight barrier protection for the cargo. For the present simulation the original hatch cover dimensions are used (21000 × 14000 × 300 mm). The principle objective of the present paper is aimed at proposing a light-weight material, so called glass fibre reinforced plastic material over the existing steel to reduce the weight for the cargo ship to improve the efficiency by reducing fuel consumption so that dead weight is downgraded. Glass fibre reinforced hatch cover also reduces man power for the process of handling the hatch cover. Based upon the finite element analysis outcomes of different grid geometries are Square, Inclined, Diamond, Honeycomb optimal core grid of hatch cover was chosen. A scaled down model of hatch cover using glass fibre reinforced plastic with an optimal grid structure has been also developed in this paper.

APPLICATION OF FUZZY FMEA TO PERFORM AN EXTENSIVE RISK ANALYSIS IN MARITIME TRANSPORTATION ENGINEERING

The nature of maritime transportation involves numerous hazards, which can lead to serious consequences for human life, marine environment and ship. Therefore, achieving a high level of safety is recognised as paramount in maritime industry (Akyuz, 2016). In order to achieve this purpose, this paper prompts a fuzzy based Failure Mode and Effects analysis (FMEA) to perform an extensive risk analysis in the maritime transportation industry. The method has capable of identifying potential failures and calculating risk priority number (RPN) by capturing nonlinear casual relationships between the failures. The proposed method is applied to hatch cover failures in operational aspects in bulk carrier ships since potential failures of hydraulic hatch covers have serious concerns for ship owners. Besides its theoretical insight, the paper has practical benefits to ship owners, superintendents as well as safety professionals by identifying potential failure and offering early corrective actions.

Edge-based cover recognition and tracking method for an AR-aided aircraft inspection system

Cabin hatch cover plays an important role for a typical aircraft to ensure the aircraft quality and flight safety. In the test flight inspection and routine maintenance of an aircraft, one crucial step is to open cabin hatch covers one by one for detailed inspection. Authorized operators suffer from difficulties to recognize different covers with similar shapes and different inspection requirements. In this paper, an edge-based cover recognition and tracking method is proposed to recognize different hatch covers with similar shapes. First, a fast edge feature is proposed to describe image contours with simple geometric constraints. Second, based on the edge feature, a novel cover descriptor, consisting of shape and position description vectors, is presented to recognize those different covers with similar shapes. Third, on the basis of recognized cover landmarks, a direct visual odometry–based camera tracking method is presented to improve the robustness of cover recognition. The experiments are implemented in a piece of simplified mockup of aircraft cabin skin, and the results show that the proposed method has good practicability and real-time property. Meanwhile, the tracking accuracy is also good enough in the augmented reality inspection environment.

Transverse ultimate capacity of U-type stiffened panels for hatch covers used in ship cargo holds

ABSTRACT Due to cargo loads or weather loads above decks and elastic deformations of the ship’s hull, hatch covers will subject to transverse loads. However, the existing formulas for transverse ultimate capacity evaluation are not applicable to U-type panels due to a higher rotation constraint. This paper is to find an accurate evaluation method of transverses ultimate capacity for U-type stiffened panels, in order to know about its true safety margin. One hundred and five U-type stiffened panels are designed to cover the common scope of plate aspect ratio α and plate slenderness ratio β in hatch cover structures. Based on the nonlinear FE calculations, the critical factors are analyzed, and then a simple formula is proposed, which can be used to predict transverse ultimate capacity. At last, it is proved that the U-type stiffener will have a great influence on the light-weight design compared with common stiffeners of open profile.

Ultimate strength of U-type stiffened panels for hatch covers used in ship cargo holds

ABSTRACT The U-type stiffener is widely used in hatch cover design for cargo holds due to its easier fabrication, maintenance and painting. However, its ultimate strength evaluation method under axial compression is still unclear. The existing formula for ultimate strength evaluation of stiffened panel is not applicable to U-type stiffened panels of hatch cover with thinner deck plate, wider plate breadth between stiffeners, and longer stiffener span. This paper is to find an accurate method for evaluating ultimate strength of U-type stiffened panel for hatch cover. Based on extensive non-linear FE results, a simple formula is proposed to evaluate the ultimate strength of the U-type stiffened panel under axial compression, which is well in agreement with the FE results and 30 model test results. At last, it is proved that the U-type structure will have a great influence on the lightweight design of hatch cover.

Study into Improvement of the Hatch Covers of General-Purpose Open Wagons to Provide Strength under Operational Loading Diagrams

The article presents the results of research into the strength of the hatch covers of general-purpose open wagons. It was detected that strength of the standard hatch covers is not provided in operational loading diagrams. Therefore, new designs of the hatch covers for open wagons were proposed. The results of the strength calculation, implemented with the finite element method, make it possible to conclude that at basic and additional operational loading diagrams the strength values for proposed designs of hatch covers do not exceed the admissible values. The research conducted can contribute to a higher strength of the carrying structures of the bodies of general-purpose open wagons in operation, thus, guaranteeing a higher operational efficiency of the rail transport.

STRUCTURAL-FUNCTIONAL DESCRIPTION OF THE HATCH COVER CONSTRUCTION

Purpose. The work aims at structural-functional description of the existing construction of hatch covers of gondola cars to find possible ways of their modernization and improvement. Methodology. The research and analysis are based on principles of morphological study of technical systems and systems approach. The research takes into account the results of the leading research on the topic, the authors' own development, mathematical justification and computer modeling. Calculation of the structural elements of the rolling stock was carried using modern normative and developed methodologies. Findings. The system approach in creating an innovative hatch cover allowed the design to be presented in the form of a series of interconnected and interacting subsystems, taking into account the main factors of their functioning. Authors developed the structural-functional model of the hatch cover of the gondola car, which showed that the hatch cover plate is the basic element, the structural-parametric and functional properties of which determine the corresponding characteristics of other nodal and base elements of its design. We established that the main functions of the hatch cover are distributed through the constituent elements of the first hierarchical level (between nodes): the frame serves as the reinforcing element of the plate and the base for installing other nodes, except the torsion ones. The proposed theoretical propositions, methodological foundations and practical methods of structural and functional analysis are expedient for using in the search for optimization ways and other elements of rolling stock, as well as objects of transport engineering. Originality. The methodological foundations for the creation of a structural and functional description of the hatch cover are proposed and the results of its implementation are presented, which can be used in studies of the processes of their functioning, perception and redistribution of different types of loads, taxonomy, increasing the degree of their ideality, identification of objects considered in design, repair. Practical value. The structural-functional description allowed projecting an innovative design of the hatch cover, including its frameless execution, a model with a convex design of the plate in the direction of counteracting the mass of the cargo. Using the proposed models of hatch covers, effective modernization of the domestic park of gondola cars is possible.

Application of Fuzzy FMEA to Perform an Extensive Risk Analysis in Maritime Transportation Engineering

The nature of maritime transportation involves numerous hazards, which can lead to serious consequences for human life, marine environment and ship. Therefore, achieving a high level of safety is recognised as paramount in maritime industry (Akyuz, 2016). In order to achieve this purpose, this paper prompts a fuzzy based Failure Mode and Effects analysis (FMEA) to perform an extensive risk analysis in the maritime transportation industry. The method has capable of identifying potential failures and calculating risk priority number (RPN) by capturing nonlinear casual relationships between the failures. The proposed method is applied to hatch cover failures in operational aspects in bulk carrier ships since potential failures of hydraulic hatch covers have serious concerns for ship owners. Besides its theoretical insight, the paper has practical benefits to ship owners, superintendents as well as safety professionals by identifying potential failure and offering early corrective actions.

Weight reduction and strengthening of marine hatch covers by using composite materials

The application of composites as an alternative material for marine steel hatch covers is the subject of this study. Two separate approaches are considered; weight reduction approach and strengthening approach. For both approaches Finite Element Analysis (FEA) was performed using ANSYS software. Critical design parameters of the composite hatch cover and FEA are discussed in details. Regarding the weight reduction approach; steel hatch covers of a bulk carrier were replaced by composite covers and a weight reduction of 44.32% was achieved leading to many benefits including fuel saving, Deadweight Increment and lower center of gravity of the vessel. For the strengthening approach; the foremost hatch cover was strengthened to withstand 150% of the load required by IACS for safer navigation while no change in weight was made between the steel and composite covers. Results show that both approaches are feasible and advantageous.

Design and analysis of composite panel for impact loads in marine environment

Impact loads from incoming waves always challenge the strength of structural parts of a ship. Modern high-speed crafts including naval vessels are subjected to impact loads during high speed and sudden manoeuvre. Wave slamming may damage structural parts and cause flooding of compartments due to impact. Hydrodynamic impact load results in structural damage in conventional marine vehicles. Loads during cargo loading, unloading, shipping of green water, impact with icebergs etc. come under low-velocity impact loads. The structural parts of a ship can also be damaged due to the impact of collision with icebergs as in the case of the Titanic accident. Weapon discharge, flight operation, bulk cargo operation and collision with other structures are other examples of impact load acting on marine vehicles. Severe hydrodynamic impact load may cause damage of shell plating, collapse of bow part, damage of hatch covers, collapse of hull girder etc. Such structural parts should possess sufficient impact strength. Composite shells can be used for hull, deck or hatch covers of bulk carriers to reduce the weight of vehicle and to indirectly increase the pay load capacity. In the present work, cost-effective composites are prepared by adding fillers to improve impact strengths and tested to verify the same. The main objective of the study is to develop a cost-effective composite to be used as part of hull, deck and hatch cover of bulk carrier. Feasibility and selection of fillers to improve impact strength are established. Prior to this, different sizes of fillers and the chemical treatment of filler with acid were considered. Calcium carbonate (CaCO3), silicon carbide (SiC) and alumina (Al2O3) are considered with glass epoxy composite for the above analysis. The additional impact strength due to the application of fillers is determined using Izod impact strength tests. Contact force is considered as a scale parameter for the impact response for composite laminates. Contact force is the force against impact load on composite structures. Contact force and deflection history of composite panels are affected by a number of parameters such as fibres angle, laminate geometry, impactor energy, stiffeners, surface area of impactor and loading eccentricity. Effects of all possible parameters are included and their influence on the response is determined using the well-known package based on finite element method (FEM), ABAQUS. The FEM analysis of Khalili et al. (2011 Compos Struct 93:1363–1375) is used for comparison of results of the present numerical analysis. The study leads to many new insights to designers of cost-effective composite structures.

A risk-based first-principles approach to assessing green seas loading on the hatch covers of bulk carriers in extreme weather conditions

This paper aims to present and explain the work undertaken at the SSRC on the Safety of Bulk Carriers in extreme weather conditions over the past 3 years, to draw conclusions deriving there from, concerning key influencing design, operational and environmental parameters and to offer recommendations regarding the rule development process and on the way forward considering research, development and implementation to ship design and operation with the view to improving the safety of these ships cost-effectively. In severe storms, hatch covers of low freeboard vessels such as bulk carriers are the first-line of protection against flooding. Present methods of hatch covers design are still empirical because impact loads due to green seas and structural behaviour due to this type of loads have not been examined, hence not known accurately. The loading due to green seas is implicitly non-linear and, as model test results demonstrated, bulk carriers in extreme conditions are exposed to significant loads, which in some cases exceed current design standards. Since the consequences of hatch cover failure are potentially catastrophic, the risk of this happening should be quantified in probabilistic terms as required by modern safety standards. To this end, the paper aims to propose and implement a methodology for estimating probabilities of deck wetness and impact loads due to green seas as a function of key design and operational parameters.

Collapse strength of hatch cover of bulk carrier subjected to lateral pressure load

A series of elastoplastic large deflection FEM analyses has been performed on hatch covers of bulk carriers subjected to lateral load. Two types of hatch covers are considered which are the folding type and the side-sliding type. For the folding-type cover, one size is considered which is for Handy size bulk carrier, whilst for the side-sliding-type cover, two sizes are considered which are for Panamax and Cape size bulk carriers. For each type, two hatch covers are selected which are designed in accordance with the old ICLL rule and new IACS rule, respectively. Calculated collapse strengths are compared with individual design loads, and a strength assessment is performed. On the basis of collapse behaviour observed in FEM analyses, a simple method is proposed to evaluate the collapse strength of a hatch cover subjected to lateral load. It is confirmed that the collapse strength is accurately predicted by the proposed method.

Plastic Collapse Strength of Hatch Cover of Bulk Carrier against Green Sea Load (2nd Report)

After the casualty of M.V.Derbyshire, the strength of a hatch cover of a Bulk Carrier has been discussed at the International Association of Classification Societies (IACS) to prevent the occurrence of similar casualties, and a new unified requirement, S21, came into effect in 1977. In the present paper, elastoplastic large deflection FEM analysis is performed on four hatch covers of a side sliding type designed by the old rule in the International Convention on Load Lines (ICLL, 1966) and the new IACS requirement, respectively. It was found that the hatch cover designed by the new IACS rule has appropriate and enough strength. Based on the simulated collapse behaviour by the FEM, a simplified method is proposed to evaluate the plastic collapse strength of a hatch cover of a side sliding type. It is demonsrated that the proposed method gives accurate collapse load.

On-Board Dose Measurement and its Monte Carlo Analysis in a Low Level Waste Shipping Vessel

AbstractOn-board dose measurements were made in a shipping vessel for low level radioactive wastes, the Seiei Maru. The measured values are much smaller than the regulation values both on the hatch covers and in the accommodation area. The dose equivalent rates on the hatch cover are analysed by using a continuous energy Monte Carlo code, MCNP 4B, with two kinds of calculational models. One is the detailed model with the geometry of containers and LLW drums, and an asymmetrical source distribution. The results of the detailed calculation approached the shape of the measured dose rate distribution graphs. The other is the simplified model that mixes source volume uniformly. The calculated values obtained with the simplified model are twice as large as those calculated with the detailed model.

Plastic Collapse Strength of Hatch Cover of Bulk Carrier against Green Sea Load (1st Report)

After the casualty of M.V.Derbyshire, United Kingdom insisted to increase the strength of a hatch cover of a Bulk Carrier to prevent the occurrence of similar casualties. This had been discussed at the International Association of Classification Societies (IACS), and a new unified rule, S21, came into effect. In the present paper, elastoplastic large deflection analysis is performed on two hatch covers of a folding type designed by the old rule in the International Convention on Load Lines (ICLL), 1966 and the new IACS rule, respectively. Based on observations on the simulated collapse behaviour by FEM, a simplified method is proposed to evaluate the plastic collapse strength of a hatch cover of a folding type. It is demonstrated that the proposed method gives accurate collapse load. At the end, strength of old and new hatch covers are assessed comparing the evaluated collapse strength with design loads specified by the rules. It is concluded that the hatch cover designed by the new IACS rule has appropriate and enough strength.

Measurement of Dose Rates and Monte Carlo Analysis of Neutrons in a Spent-Fuel Shipping Vessel

On-board experiments were carried out in a spent-fuel shipping vessel, the Pacific Swan, in which 13 casks of TN-12A and Excellox 3 were loaded in five holds, and neutron and gamma-ray dose rates were measured on the hatch covers of the holds. Before shipping those casks, dose rates were also measured on the cask surfaces, one by one, to eliminate radiation from other casks. The Monte Carlo coupling technique was employed successfully to analyze the measured neutron dose rate distributions in the spent-fuel shipping vessel. Through this study, the Monte Carlo coupling code system, MORSE-CG/CASK-VESSEL, on which the MORSE-CG code was based, was established. The agreement between the measured and the calculated neutron dose rates on the TN-12A cask surface was quite satisfactory. The calculated neutron dose rates agreed with the measured values within a factor of 1.5 on the hold 3 hatch cover and within a factor of 2 on the hold 5 hatch cover in which the concrete shield was fixed in the Pacific Swan.

Investigations on Deck Wetness of Hatch Covers

In order to improve the hatch covers of a container ship, the calculations on deck wetness are applied to predict the water leakage into a cargo hold.The results obtained by the calculations are as follows : 1) The quantity of water flow into a cargo hold under the heavy weather is small, even where the gaskets of a hatch cover are eliminated.2) The short term probability of deck wetness is small.The flow into the foward cargo hold is less than 10 m3/h, under the sea conditions of significant wave height of 710 m.3) The long term probability of deck wetness is also not so high.According to these results, the improvement of hatch covers, such as elimination of gaskets, will be successfully adopted.