Effect of Geometric Parameters of New Semisubmersible Platform on Stability and Hydrodynamic Performance

2021 ◽  
Author(s):  
Tianying Wang ◽  
Yanjun Zhou ◽  
Honglin Tang ◽  
Shihua Zhang ◽  
Haiqing Tian
Keyword(s):  
Geometric Parameters ◽  
Hydrodynamic Performance ◽  
Geometrical Parameters ◽  
Main Body ◽  
Floating Bodies ◽  
Full Picture ◽  
New Type ◽  
Design Plan ◽  
The Stability ◽  
Shape Characteristics

Abstract The JCSM concept (short for Jackup Combined Semisubmersible Multifunction Platform) is a new type of semisubmersible platform presented by the first author, which overcomes the shortcomings of the available semisubmersible platforms, and combines the advantages of the traditional semisubmersible platform, the Jackup platform and the new FPSO concept - IQFP. Due to the complicated interaction between stability and hydrodynamic performance, it is necessary to explore the effect of geometrical parameters of the main body on the stability and hydrodynamic performance in order to obtain the optimal design plan of a JCSM platform. Firstly, the structure components and innovations of the JCSM were briefly reviewed in order to facilitate readers to understand its full picture. Then, six independent geometric parameters were selected by carefully studying the shape characteristics of the initial design plan of a JCSM study case. Furthermore, the stability heights and motion responses of various floating bodies of the JCSM case with different geometric parameters in wave were calculated using boundary element method based on potential flow theory. Lastly, effect of the shape parameters on stability and hydrodynamic performance of the JCSM was qualitatively evaluated. The research would shed lights on the shape design of the JCSM main body.

scholarly journals DYNAMICS INTERACTION OF THE SHARE MOLE PLOW WITH SOIL IN THE FORMATION OF THE CAVITY FORIMPERVIOUS SCREEN

2020 ◽  
pp. 44-52
Author(s):  
Olena Solona ◽  
Vladimir Kovbasa ◽  
Oleksandr Melnik
Keyword(s):  
Mechanical Properties ◽  
Contact Zone ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Geometrical Parameters ◽  
Problem Solution ◽  
Equilibrium Equations ◽  
Stress Components ◽  
Soil Irrigation ◽  
The Stability

To maintain moisture and best spread it in the horizontal direction under in-soil irrigation of agricultural plants there is a necessity of laying moisturizers together with an impermeable screen. For this purpose, share mole plow can be used. Substantiation of tool's geometrical parameters and modes of operation is an actual scientific problem. Solution of this problem requires formalizing the soil as the medium on which the tool is directed, as well as formalizing the interaction of the tool with the soil. This article discusses the dynamics of the ploughshare forming a horizontal gap into which the anti-filter screen extends. For this, the interaction of the plowshare of the mole with the soil in the contact zone during compaction of the walls of the formed cavity is under considered. Herewith, the degree of compaction of the walls affects the stability of the arch of the formed cavity. During the study, the soil is presented in the form of an elastic viscous deformable medium, and the ploughshare - in the form of an absolutely solid. The surface of this solid is described by a three-dimensional equation in an implicit form, the coefficients of which characterize the geometric parameters of the tool. In a previous article, the authors obtained functions of the rates of soil deformations from the action of the tool. Based on the strains functions with use the physical equations of the connection between stress and strains, the functions of the stress components on the mechanical properties of the soil and the parameters of the tool are obtained. The stress components obtained in the contact zone of the plowshare with the soil made it possible to determine the function of changing the specific volume of the soil. This function is inversely proportional to soil density. The use of equilibrium equations on the contact surface made it possible to determine the components of the forces that act from the soil side on the ploughshare. Integration of the obtained components of the distributed forces over the ploughshare surfaces made it possible to obtain the sum of the resistance forces to the ploughshare movement, depending on the mechanical properties of the soil and tool parameters. As a result of the study, rational parameters of the equation coefficients of the ploughshare surface that characterize its geometric parameters are determined.

Parametric Optimization of Dental Implants

2020 ◽  
Vol 22 (4) ◽  
pp. 1061-1076
Author(s):  
Wafa Bensmain ◽  
Mohammed Benlebna ◽  
Boualem Serier ◽  
Bel Abbes ◽  
Bachir Bouiadjra
Keyword(s):  
Dental Implants ◽  
Clinical Success ◽  
Equivalent Stress ◽  
Radius Of Curvature ◽  
Geometrical Parameters ◽  
Neck Size ◽  
Biomechanical Behavior ◽  
Dynamic Charging ◽  
The Stability ◽  
Masticatory Process

AbstractOsseointegration is a fundamental phenomenon of dental implantology. It ensures the stability, the safety and the durability of dental implants and predictable clinical success in long-term. The geometric form of the implant is a defining parameter of osseointegration and implant-bone charge transfer. This is the essential constitutes of this study. In fact, we demonstrate using the finite elements method with tridimensional numerical computations, that the geometrical parameters of the implant conditionate the level and the repartition of the stresses, induced in the cortical bone and the spongy bone during the masticatory process, simulated here by dynamic charging. The effect of several parameters [size and conicity of the implant neck, size and radius of curvature of the implant apex] and the shape of the implant corps on the biomechanical behavior of the bone. The latest was analyzed in terms of variation of the equivalent stress induced in the bone. The purpose of this analysis was the developing of an implant form allowing stress relaxation, during the mastication process, in the living tissue.

Genetic algorithm application for optimization of geometry of synchronous electric motor with permanent magnets by criterion of electromagnetic torque

2019 ◽  
pp. 56-62
Author(s):  
I. N. Belezyakov ◽  
K. G. Arakancev
Keyword(s):  
Genetic Algorithm ◽  
Electric Motor ◽  
Permanent Magnets ◽  
Evolutionary Optimization ◽  
Electric Machines ◽  
Geometric Parameters ◽  
Geometrical Parameters ◽  
Electromagnetic Torque ◽  
Automatic Control Systems ◽  
Optimization Of Geometry

At present time there is a need to develop a methodology for electric motors design which will ensure the optimality of their geometrical parameters according to one or a set of criterias. With the growth of computer calculating power it becomes possible to develop methods based on numerical methods for electric machines computing. The article describes method of a singlecriterion evolutionary optimization of synchronous electric machines with permanent magnets taking into account the given restrictions on the overall dimensions and characteristics of structural materials. The described approach is based on applying of a genetic algorithm for carrying out evolutionary optimization of geometric parameters of a given configuration of electric motor. Optimization criteria may be different, but in automatic control systems high requirements are imposed to electromagnetic torque electric machine produces. During genetic algorithm work it optimizes given geometric parameters of the electric motor according to the criterion of its torque value, which is being calculated using finite element method.

scholarly journals Special Finite Elements with Adaptive Strain Field on the Example of One-Dimensional Elements

2021 ◽  
Vol 11 (2) ◽  
pp. 609
Author(s):  
Tadeusz Chyży ◽  
Monika Mackiewicz
Keyword(s):  
Finite Elements ◽  
Strain Field ◽  
Main Idea ◽  
Deformation Field ◽  
Geometrical Parameters ◽  
Single Element ◽  
One Dimensional ◽  
New Type ◽  
Self Adaptation ◽  
Adaptation Method

The conception of special finite elements called multi-area elements for the analysis of structures with different stiffness areas has been presented in the paper. A new type of finite element has been determined in order to perform analyses and calculations of heterogeneous, multi-coherent, and layered structures using fewer finite elements and it provides proper accuracy of the results. The main advantage of the presented special multi-area elements is the possibility that areas of the structure with different stiffness and geometrical parameters can be described by single element integrated in subdivisions (sub-areas). The formulation of such elements has been presented with the example of one-dimensional elements. The main idea of developed elements is the assumption that the deformation field inside the element is dependent on its geometry and stiffness distribution. The deformation field can be changed and adjusted during the calculation process that is why such elements can be treated as self-adaptive. The application of the self-adaptation method on strain field should simplify the analysis of complex non-linear problems and increase their accuracy. In order to confirm the correctness of the established assumptions, comparative analyses have been carried out and potential areas of application have been indicated.

scholarly journals Numerical and Experimental Investigation on Key Parameters of the Respimat® Spray Inhaler

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Yi Ge ◽  
Zhenbo Tong ◽  
Renjie Li ◽  
Fen Huang ◽  
Jiaqi Yu
Keyword(s):  
High Speed ◽  
Fine Particles ◽  
Geometric Parameters ◽  
Metered Dose Inhalers ◽  
Geometric Pattern ◽  
Long Duration ◽  
Metered Dose ◽  
New Type ◽  
Computational Fluid Dynamics Cfd ◽  
Spray Velocity

Respimat®Soft MistTM is a newly developed spray inhaler. Different from traditional nebulizers, metered-dose inhalers, and dry powder inhalers, this new type of inhaler can produce aerosols with long duration, relatively slow speed, and a high content of fine particles. Investigating the effect of the key geometric parameters of the device on the atomization is of great significance for generic product development and inhaler optimization. In this paper, a laser high-speed camera experimental platform is built, and important parameters such as the geometric pattern and particle size distribution of the Respimat®Soft MistTM are measured. Computational fluid dynamics (CFD) and the volume of fluid method coupled with the Shear Stress Transport (SST) k-ω turbulence model are applied to simulate the key geometric parameters of the device. The effects of geometric parameters on the spray velocity distribution and geometric pattern are obtained. The angle of flow collision, the sphere size of the central divider and the length and width of the flow channel show significant impacts on the spray atomization.

Experimental Study on the Stability Performance and Turning Motion of Multi-Connection VAWT

2021 ◽  
Author(s):  
Saika Iwamatsu ◽  
Yasunori Nihei ◽  
Kazuhiro Iijima ◽  
Tomoki Ikoma ◽  
Tomoki Komori
Keyword(s):  
Scaling Law ◽  
Type A ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Water Tank ◽  
Type B ◽  
Floating Bodies ◽  
Stability Performance ◽  
Turning Motion ◽  
The Stability

Abstract In this study, a series of dedicated water tank tests were conducted in wind and waves to investigate the stability performance and turning motion of Floating Offshore Wind Turbine (FOWT) equipped with two vertical axis wind turbines (VAWT). The FOWT targeted in this study is called Multi-connection VAWT, which is a new type of FOWT moored by Single-Point-Mooring (SPM) system. We designed and manufactured two types of semi-submersible floating bodies. One is a type in which VAWTs are mounted in two places of a right-angled isosceles triangle (Type-A) on a single floater, and the other is two independent units equipped with VAWTs on two separate floaters centered on a moored body. This is a type in which two semi-submersible floating bodies are lined up in a straight line (Type-B). The experimental conditions were determined by scaling down to 1/100 using Froude’s scaling law based on a wind thrust load of 320 kN (rated wind speed of 12 m/s) assuming an actual machine. In the free yawing test in waves, Type-A turned downwards, while Type-B was barely affected by the waves. Furthermore, in the free yawing test in wind, both Type-A and Type-B turned leeward and stabilized at a final point where the wind load was balanced.

scholarly journals Evaluation of Lipases from Wild Microbial Strains as Biocatalysts in Biodiesel Production

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 53 ◽  
Author(s):  
Carlos Luna ◽  
Diego Luna ◽  
Felipa Bautista ◽  
Juan Calero ◽  
Antonio Romero ◽  
...  
Keyword(s):  
Biodiesel Production ◽  
Purification Process ◽  
Bacterial Strains ◽  
Production Methods ◽  
Mild Conditions ◽  
New Type ◽  
Microbial Strains ◽  
The Stability ◽  
Microbial Strain ◽  
Biodiesel Industry

In this study, the evaluation of the catalytic behavior of several wild bacterial strains in the 1,3-selective ethanolysis of triglycerides with ethanol to produce a new type of biodiesel (Ecodiesel) that integrates glycerol as monoacylglycerols was carried out. The Ecodiesel production not only avoids the elimination of glycerol, which is largely generated as a by-product in the biodiesel industry, but also results in an increase in the biofuel yield. The wild microbial strain samples were obtained from several lipophilic organisms. In addition to evaluate the enzymatic extracts, the minimum grade of purification of the strains, necessary to obtain similar results to those attained with commercial lipases was studied. This purification treatment included a dialysis followed by a lyophilization process. Such extracts were directly used as biocatalysts in the transesterification reaction of sunflower oil with ethanol, attaining much better results (yield close to 100%) than those obtained with strains which were not submitted to the purification process (yields lower than 10%). Furthermore, the results here obtained are similar to those obtained with commercial lipases but were achieved under mild conditions and lower reaction time (2 h). In addition, the stability of the enzymatic extracts was corroborated by subsequent reactions, showing no loss of activity. Thus, this study brings to light that enzymatic extracts obtained by a very simple purification process can be economically competitive with the conventional biodiesel production methods.

scholarly journals Hydrodynamic Analysis for the Morphing Median Fins of Tuna during Yaw Motions

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiaohu Li
Keyword(s):  
Numerical Method ◽  
Hydrodynamic Forces ◽  
The Body ◽  
Robotic Fish ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Analysis ◽  
Dorsal Fin ◽  
The Stability ◽  
Median Fins

Tuna can change the area and shape of the median fins, including the first dorsal, second dorsal, and anal fins. The morphing median fins have the ability of adjusting the hydrodynamic forces, thereby affecting the yaw mobility of tuna to a certain extent. In this paper, the hydrodynamic analysis of the median fins under different morphing states is carried out by the numerical method, so as to clarify the influence of the erected median fins on the yaw maneuvers. By comparing the two morphing states of erected and depressed, it can be concluded that the erected median fins can increase their own hydrodynamic forces during the yaw movement. However, the second dorsal and anal fins have limited influence on the yaw maneuverability, and they tend to maintain the stability of tuna. The first dorsal fin has more lift increment in the erection state, which can obviously affect the hydrodynamic performance of tuna. Moreover, as the median fins are erected, the hydrodynamic forces of the tuna’s body increase synchronously due to the interaction between the body and the median fins, which is also very beneficial to the yaw motion. This study indicates that tuna can use the morphing median fins to adjust its mobility and stability, which provides a new idea for the design of robotic fish.

Effect of Heat-Treatment Time on Microstructure and Mechanical Properties of Mg-5Gd-2Y-2Zn-0.5Zr Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1384-1389 ◽  
Author(s):  
Ling Gang Meng ◽  
Can Feng Fang ◽  
Peng Peng ◽  
Nai Pu Li ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Treatment Time ◽  
Time Range ◽  
Lpso Phase ◽  
High Temperature Heat Treatment ◽  
Lpso Structure ◽  
The Matrix ◽  
New Type ◽  
The Stability

Microstructure evolution of Mg-5Gd-2Y-2Zn-0.5Zr alloy during high temperature heat-treatment at 500°C in the time range 10-70h was investigated. The results show that after adding the element Y, the as-cast Mg-5Gd-2Y-2Zn-0.5Zr alloy forms the Mg12Zn(Y,Gd) phase with 18R-LPSO structure at the grain boundary. During heat-treatment at 500°C, the stability of 18R-LPSO structure is weakened by Gd atoms, parts of LPSO phases dissolve gradually into the matrix with time prolonged and a new type Mg(Y,Gd)Zn phase come into being. LPSO phase in the grain boundary can ensure the ultimate tensile strength and elongation of the alloy, and effect of dissevering on the LPSO phase by Mg(Gd,Y)Zn phase results the decrease of UTS and elongation.

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