Bulkhead Design Research Articles

Improved honey badger algorithm based on elementary function density factors and mathematical spirals in polar coordinate systema

The Honey Badger Algorithm (HBA) is a new swarm intelligence optimization algorithm by simulating the foraging behavior of honey badgers in nature. To further improve its convergence speed and convergence accuracy, an improved HBA based on the density factors with the elementary functions and the mathematical spirals in the polar coordinate system was proposed. The algorithm proposes six density factors for attenuation states based on elementary functions, and introduces mathematical expressions of the polar diameters and angles of seven mathematical spirals (Fibonacci spiral, Butterfly curve, Rose spiral, Cycloid, Archimedean spiral, Hypotrochoid and Cardioid) in the polar coordinate system based on the density factors with the best synthesized effect to replace the foraging strategy of honey badger digging pattern in HBA. By using 23 benchmark test functions, the above improvements are sequentially compared with the original HBA, and the optimization algorithm with the best improvement, α4CycρHBA, is selected to be compared with SOA, MVO, DOA, CDO, MFO, SCA, BA, GWO and FFA. Finally, four engineering design problems (pressure vessel design, three-bar truss design, cantilever beam design and slotted bulkhead design) were solved. The simulation experiments results show that the proposed improved HBA based on the density factors with the elementary functions and the mathematical spirals of the polar coordinate system has the characteristics of balanced exploration and expiration, fast convergence and high accuracy, and is able to solve the function optimization and engineering optimization problems in a better way.

Analysis and design of the gas generator multifunctional bulkhead considering the thermal and structural loads

The operation of gas generators brings relatively high thermo-mechanical loads on the gas generator structure. The objective of this article is to determine the operating conditions, in terms of mechanical loads at extremely high temperatures in very limited and narrow space, of a multifunctional bulkhead for application on specific kinds of gas generators with back-to-back rotor concept. The paper contains numerical analysis and experimental investigation for determining the loads and behavior of the structure. Numerical analysis indicates that there is significant influence of the Tesla turbine effect on flow parameters. Also, uneven pressure distribution and significant thermal loads are identified. With experimental investigation and subsequent exploitation tests, it was concluded that the presented methodology identifies the operating conditions, truthfully simulates the bulkhead stress state and deformations and that the presented design solution satisfied all demands. Regarding results obtained by these numerical simulations, the innovative design solution for the multifunctional bulkhead was proposed.

Lightweight design and experimental investigation of codirectional corrugated steel fire bulkheads on a cruise ship

A lightweight design method based on topography optimization theory, which can adaptively determine locations, numbers and topography of the codirectional beads of sandwich bulkheads is proposed. Mathematical optimization formulations for the bead topography design of sandwich bulkheads that considering weight objective and strength and buckling constraints are established. Taking a fireproof bulkhead design in the superstructure of a cruise ship as an example, the design process based on the proposed method is demonstrated. A full-scale sandwich bulkhead specimen is selected and manufactured for comparison with the stiffened bulkhead. Then, a load-bearing fire-resisting test is carried out on the specimen. The test results show that the structure of the unexposed side of the specimen is intact and that there is no smoke emission. The average and maximum increases in temperature on the unexposed side are 80.2 °C and 104 °C, and the maximum axial deformation and the average axial deformation rates are 7.9 mm and 3.8 mm/min, respectively. The new sandwich bulkhead can be regarded as a “load-bearing fire-resisting divisions 30” class bulkhead because these results meet the requirements of the 2010 Code for Application of Fire Test Procedures. However, its weight is just 73.86% that of the stiffened bulkhead.

Design and experimental study of lightweight fireproof bidirectional bead bulkheads in a cruise ship

The design of cruise bulkheads faces a challenge on the balance of lightweight, load-bearing capacity and fireproof performance. The existing steel stiffened bulkheads exhibit heavy weight and complicated manufacturing process, while lightweight (composite and aluminum) bulkheads suffer from high cost and poor load-bearing capacity. A lightweight design method based on the topography optimization theory, which can adaptively determine locations, numbers and topography of the bidirectional bead of sandwich bulkhead is proposed for cruise ships. Mathematical optimization formulations for bead topography design of sandwich bulkheads considering weight objective and strength and buckling constraints are established. Taking a fireproof bulkhead design in the superstructure of a cruise ship as an example, the design process based on the proposed method is demonstrated, including the fire protection design of insulation materials, the selection of design domains in the bead topography optimization, the definition of design variables, and the refined design of the final bead parameters. A full-scale lightweight bidirectional bead steel sandwich bulkhead (the specimen) is selected and manufactured by comparing with the stiffened bulkhead. Then a load-bearing fire-resisting test of the specimen designed is carried out. The test results show a weight reduction of 20.56% for the new designed bulkhead compared with the conventional one, and reached the fire-resisting divisions 60 class meeting the requirements of integrity, insulation and load-bearing. This design method provides a new way to alternatively design fire-resisting bulkheads.

Design of Light Fireproof Enclosure Bulkheads Based on Topography Optimization for Cruise Ships

Design of Light Fireproof Enclosure Bulkheads Based on Topography Optimization for Cruise Ships

Design and topological optimization of rear pressure bulkhead for a typical aircraft

Purpose The purpose of this paper is to evaluate the model of a rear pressure bulkhead with different design optimizations to meet the pressurized cabin requirements of an aircraft. Design/methodology/approach This paper presents the results of the static analysis of a dome-shaped rear pressure bulkhead model designed in Catia-v5. Numerical analysis of model meshed in hyper-mesh and solved using Opti-Struct for iterative design optimizations. Findings All the iterative models are analyzed at 9 Psi. Rear pressure bulkhead designed with L-section stringer shows better results than the model optimized with T-section stringer for the same thickness. The model optimized with L-shaped stinger also reduces the weight of the bulkhead without affecting the structural integrity. Practical implications It has been concluded in this paper that the selection of specific shapes of the stringers shows a significant influence on weight reduction. Originality/value This paper provides a topical, technical insight into the design and development of a rear pressure bulkhead. It also outlines the future development of dome-shaped rear pressure bulkhead.

An Application of Reinforced Polyurethane Foam in Design of the Common Bulkhead for Cryogenic Tanks

By using the material of reinforced polyurethane (RPU) foam, the common bulkhead is devised for cryogenic tanks in this paper. Properties of RPU foam are obtained through experiments. Based on the properties, the structure is designed with the integration of special features including lightweight, easy to manufacture, load bearing and thermal insulation. Based on numerical simulation, thermal analysis, stability and thermal mechanical coupling behavior of the structure are analysed. The results show that the common bulkhead not only satisfies the heat insulation requirements of cryogenic tanks for liquid hydrogen and oxygen, but also keeps stability.

An application and subsequent benefits of digitalisation to pipeline engineering using a 3D pipe-in-pipe bulkhead design project case study

Digitalisation of design processes is being rapidly accepted as a major step-change in engineering of pipelines and components. Incremental digitalisation of best engineering practice, analytical portions of industry codes and iterative optimisation tasks enable multiple advantages over typical project execution models. These include (a) maintaining flexibility throughout the design process to deal with changes particularly at critical interface points, (b) utilising computing power to drive an optimised solution, (c) cost and schedule advantages and (d) development of platforms to implement in future projects. These benefits are demonstrated by detailing an application of Genesis’s small-scale digitalisation strategy, as implemented on a pipe-in-pipe (PiP) bulkhead design in the Edvard Grieg Tie-Backs engineering, procurement, construction and installation development in the North Sea. The application of this strategy involved initial scoping and production of a design platform consisting of three Python modules. The platform enabled full parameterisation of a 3D end-bulkhead finite element analysis modelling process and post-processing criteria. The flexibility of this digitalisation strategy enabled simulations of (a) multiple material configurations, such as the application or removal of corrosion resistant cladding and (b) streamlined execution of highly iterative design processes. Through this platform, parallel execution of detail design and procurement was optimised, leading to achievement of material cost savings while minimising schedule and variation impact. This example of small-scale digitalisation establishes a philosophy for the future execution of PiP design and aligns both strategic and incremental steps towards a larger digitalisation initiative.

Effect of Bulkhead Pressurization on the Vibro-Acoustic Properties of an Aft-Fuselage-Mounted Twin-Engine Aircraft

Abstract Despite widespread use of an aft-fuselage-mounted twin-engine aircraft in the business jet industry, a thorough investigation into the vibro-acoustic properties of this aircraft type has yet to be undertaken. Additionally, the effect of bulkhead pressurization on the vibro-acoustic properties of this aircraft fuselage has yet to be investigated in isolation. This work investigates the effect of bulkhead pressurization on two different designs of an aft-fuselage-mounted twin-engine aircraft: a single and a double bulkhead designs. A modal analysis, a harmonic frequency response analysis, and an acoustic response analysis were performed. A split bulkhead pressurization methodology was introduced as a means of improving structural performance without impacting passenger comfort levels in a double bulkhead aircraft. Modal coupling between components was seen to be the primary cause of increased cabin noise, peaking above 80 Hz. The bulkhead frequency response was highly dependent upon bulkhead pressurization, as the modal participation factors were significantly impacted by bulkhead pressurization. Therefore, the importance of understanding all bulkhead natural frequencies was highlighted, as the response changed as a function of bulkhead pressurization. Bulkhead resonance conditions generated a tone in the acoustic frequency response inside the passenger cabin, highlighting the importance of this component to passenger comfort levels.

Design and simulation analysis of trimaran bulkhead based on topological optimization

In order to improve the overall performance of trimaran, the lightweight design of trimaran bulkhead is proposed by using structural topology optimization method. And ensure that the trimaran bulkhead has sufficient structural strength while the structural quality is reduced, seven structural strength checking conditions of trimaran are designed based on Rules for The Classification of Trimarans. Variable density topology optimization method is applied to calculate the bulkhead structure of trimaran before and after optimization under different working conditions. The results of calculation and optimization show that: the stress distribution on the optimized bulkhead and the maximum stress of the optimized bulkhead with different volume constraint condition in special cases are different. The maximum stress of the trimaran bulkhead before and after the bulkhead being optimized are most close in a specific case when the volume reduction rate is 50%. By comparing with the design of the actual ship bulkhead, the distribution of the connecting material of the optimized bulkhead is consistent with the distribution of the stiffeners of the trimaran bulkhead design, and the optimization result has a high similarity with the actual ship bulkhead design.

О расчетах прочности и жесткости килеватых днищевых перекрытий и выборе доковых стоек поперечных переборок корабля

This paper explains how to calculate the correction factor for keel inertia moment due to the dead rise of grillage and how to consider bulkhead plating in calculation of dock strut response to keel cribbing. The solutions described in this study are different from the commonly used ones. New formulas have been obtained for taking into account inertia moment of grillages with dead rise, as well as for calculation of Euler stresses in dock struts, and their design algorithm has also been updated. The results offer more accurate calculations of grillages with dead rises and more accurate design of transverse bulkheads in terms of conventional beam models and methods of structural mechanics.

Fatigue behaviour of orthotropic steel bridge decks with inner bulkheads

Tests on a full-scale orthotropic steel deck (OSD) specimen were conducted to investigate the effects of inner bulkheads set inside the U-ribs on the static and fatigue behaviours of the OSD. The total length and width of the OSD specimen are 5 m and 2.24 m, respectively. It contains three longitudinal floorbeams and four transversal U-ribs. U-ribs with and without inner bulkheads are symmetrically arranged in the cross section of the specimen. Finite element (FE) analyses on the OSD specimen model and sub-models were conducted to further study the effects of the inner bulkhead design and different bulkhead shapes. Results of the test and corresponding FE analysis of the specimen showed that inner bulkheads can be used to improve the fatigue life of the OSD. Meanwhile, fatigue cracking in the rib-to-bulkhead details was introduced by installing the inner bulkhead. Results of the FE analysis of the sub-models showed that the distance from the bottom edge of the inner bulkhead to the tip of the floorbeam cutout affects the stress state of the rib-to-floorbeam connection weld significantly. Additionally, the bulkhead shape affects the hot spot stress of the weld toe of the rib-to-floorbeam connection weld significantly. Thus, proper bulkhead shape should be determined by considering the specific stress distribution of the rib-to-floorbeam connection area.

The performance of armour steels with pre-layers against fragment simulating projectiles

Armour steels have proven to be promising solutions for protection against fragments from threat weapons. The area to cover for ship bulkheads is usually large, so cost of the raw material is an important driver. For new ships, additional mass can be compensated for in the design. Past research by TNO and other workers has shown that the ballistic limit V50 of armour steels against fragments is increased significantly by adding a front or pre-layer. This layer can be a variety of materials ranging from cardboard to glass. In TNO’s Laboratory for Ballistics Research a test program was conducted to study the effect of high pressure laminate, polymer and fire insulation pre-layers at the V50 and well above the ballistic limit. The high velocities are typically associated with fragments from relevant threats for warships. Fragment simulating projectiles were fired on armour steel plates of varying type and thickness with these pre-layers and measured the residual velocity and resulting hole sizes. The tests resulted in clear dependencies of the residual velocity as a function of impact velocity and pre-layer (type and thickness). Analysis of the data showed that there are several counteracting effects interacting when a pre-layer is applied to armour steel. The failure mechanism of the steel as well as the hardness and thickness of the pre-layer seem to influence the outcome of this interaction and hence the response of the steel to various pre-layers. The results of this research will be used in the design of fragment and blast resistant bulkheads for future naval ships.

Improvements in Vehicle Stiffness by Adding Internal Reinforcements

The world’s climatic conditions rises and there is a demand for environment friendly vehicle designs. The automobile industry strives hard to ensure low carbon emissions. This refers to the mass reduction and fuel consumption. This paper investigates to achieve the overall Body-in-white (BIW) bending and torsion stiffness performance using Topology optimization and light weight internal reinforcements. The potential opportunity of achieving light weight structure using the efficient way of defining the internal reinforcements has been investigated. BIW at the conceptual design phase has been considered for the research. Topology optimization was performed considering the roof rail and the rocker as the design space with an approach of achieving the improved torsion and bending stiffness performance. The optimized bulk head design locations have improved the BIW stiffness performance with minimal mass increase in the BIW. This method can be widely used at various stages of the BIW design to identify the weaker sections and then design the load path using internal reinforcements effectively. The optimized internal reinforcements has achieved higher torsion and bending performance with minimal mass addition.

Research and Development on 8-­Wavelengths Dual-Lamp Combined with Lamp and Ballast

This study was to develop the products that the Lamp and Ballast are combined for the purpose of easy installation to complement the difficulty of the installation process due to the structure of existing product which the lamp and the Ballast are separated, and that have 8-wavelengths dual-lamp structure such as solar, an advantage of more than 3 times longer life than fluorescent lamp and immediately lighting. This study developed the commercialized products that can prevent the environmental pollution caused by low efficiency and short life time of existing Lamps, and can replace the LED Lighting products which has high Glare index with high price, has also developed the variety of application for industrial, commercial, indoor and military. The applied product are Street lights, Security lights, Flood lights, Indoor lights and lights for fishing. This study solved the optimum distribution and placement of components considering the lightest weight first and thermal interference caused by combination of lamp and ballast by thermal release through applying the double bulkhead design of ballast box, and implemented the high efficiency Eco-friendly products with excellent visibility which can be applied and used for indoor and outdoor both place through high temperature and high humidity test, which has an advantage of 8-wavelengths of same spectrum of solar through the initial trial production.

Modeling the Strength Properties of Power Bulkheads in the Frame Structures

The work deals with modeling methods of frame structures, used in rocket technology. To estimate their inertia, stiffness and strength properties it is necessary to create its calculation model. Currently, a finite element method is generally used. Various finite elements and combinations thereof may constitute such models. It is obvious that parameters of design under consideration, resulting from calculation, depend on the selected calculation model. To simulate the properties of a longitudinal set of elements (stringers and longerons), as well as braces a girder (beam) idealization is offered, because their transverse dimensions are substantially smaller than the longitudinal ones. The elements of a transverse power set (frames) is a plated arch-shaped construction of variable sections with holes. Weld tubes of different diameters reinforce the holes in plates. There are cutouts in the vertical plates to mount the stringers. It is impossible to take completely into consideration the mentioned features in the frame idealization of bulkheads. Therefore, it seems more appropriate to use plate-frames for modeling the bulkheads. . The paper discusses two possible models of the bulkhead to show their stiffness properties, namely frame and plate. Describes strengths and shortcomings of represented bulkhead design schemes. Based on the test calculations shows which errors may be possible in calculating the strength properties of the bulkhead under consideration when using a frame model. Gives recommendations on the proper use of potential bulkhead models to estimate a general and local strength of the bulkhead structure. The SADAS software package developed at the Department SM8 in BMSTU was used to create the bulkhead models under study, perform their test calculations and analyze calculation results.

New methodology for light weight solutions to improve BIW structural performance using bulk head optimization

Body-in-white (BIW) is the Car body with welded sheet metal parts painted in white. Automobile companies were trying to optimize mass and improve performance with optimal mass addition. In many automotive industries many BIW designs due to aggressive mass optimization, there is a need to have smart solutions to improve BIW structure performance with very little mass increase. In this paper, a new technique of identifying the optimized internal reinforcements in the BIW at conceptual BIW design phase using Deign of experiments and Multi-objective optimization has been investigated. The paper focus on the Bending and torsion stiffness load cases to evaluate the BIW performance. Bulk head designs were designed at the major joints like A-pillar, B-pillar, C-pillar and rocker and their optimal locations to improve stiffness with minimum mass increase were identified using Design of experiments and multi objective techniques. The research shows that the optimized Bulk head design locations using the DOE technique has improved the overall BIW stiffness performance by 3.9% with 1.2% of mass addition in the BIW.

Challenges of using topology optimization for the design of pressurized stiffened panels

Topology optimization has been successfully used in several case studies in aerospace and automotive industries to generate innovative design concepts that lead to weight savings. This motivates the exploration of this new approach for the design of an aircraft flat pressure bulkhead. However, no studies were conducted on this type of structure. Therefore, this paper presents and discusses the challenges associated with the design of flat pressurized plate using topology optimization (SIMP (Solid Isotropic Material with Penalization) method). A simply supported rectangular plate is used as the design case and a typical layout is defined as a comparison basis. The mass of the interpreted design concepts are obtained with a simplified sizing approach taking into consideration stress and displacement constraints. Results show that the topology layout is not unique as is sensitive to optimization parameters. Moreover, the interpretation of the layout is challenging as they are driven by complex interactions. Finally, the performance of the topology design concept is at most comparable with the typical layout and no significant improvement is obtained. The study highlights the importance of performing an extensive topology study in order to better understand the behavior of the design before creating a concept. An improved topology design process is finally proposed in order to provide guidance to industrial designers.

Soil-Pile Coupling Analysis of Steel Sheet Pile Bulkhead under Horizontal Loads

With the development of steel sheet pile bulkhead gradually toward large-scale and deep water, natural conditions become worse and structural load rating continues to improve, design and construction of steel sheet pile bulkhead needs higher requirements. Then the stability of sheet pile bulkhead under horizontal loads becomes particularly prominent. This paper presents the displacement and stress of steel sheet pile bulkhead structure under different horizontal loads using ANSYS, which provide academic support for the design and construction of steel sheet pile bulkhead.

Sloshing-induced slamming in screen-equipped rectangular tanks in shallow-water conditions

Sloshing-induced slamming in a rectangular tank with centralized slat-screens with high solidity ratios was experimentally studied under nearly two-dimensional shallow-water conditions with large-amplitude harmonic lateral excitation. The main objective was to identify the solidity ratio that provides an optimal suppressing function on the free-surface elevation and slamming pressure on the vertical tank walls with a frequency domain containing the three lowest natural sloshing frequencies in a clean tank with a water depth-to-tank length ratio of h/l = 0.125 and a high forced sway amplitude. The experiments show that the optimal solidity ratio among four considered slat-screens is approximately 0.6-0.7 for the applied filling level and excitation amplitude in the examined forced frequency range. The results have potential applications in areas such as swash bulkhead design and liquefied-cargo tank design in ship and offshore engineering.