scholarly journals Optimization and Experimental Study of the Subsea Retractable Connector Rubber Packer based on Mooney-Rivlin Constitutive Model

2021 ◽  
Vol 9 (12) ◽  
pp. 1391
Author(s):  
Kefeng Jiao ◽  
Feihong Yun ◽  
Zheping Yan ◽  
Gang Wang ◽  
Peng Jia ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Optimization Method ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Response Surface Optimization ◽  
Multi Objective Genetic Algorithm ◽  
Design Variables ◽  
Sealing Performance ◽  
The Cross ◽  
Sectional Shape

The sealing performance of the rubber packer is of vital importance for the subsea retractable connector, and the cross-sectional shape of the rubber packer is one of the most important factors affecting it. The compression distance of the rubber packer is increased by 19.54% utilizing the established two-dimensional numerical model. In addition, a new parameter called the anti-shoulder extrusion variable was defined in this paper. Shoulder extrusion will not occur when using this variable as a constraint during simulation. In general, the upper end and the lower end of a rubber packer are subject to different constraints, and the structural parameters of the rubber packer affect each other in terms of sealing performance. Therefore, the importance and originality of this study are exploring the optimization of the thickness and chamfer angles of the upper and lower ends of the rubber packer by use of a combination of the response surface optimization method and the multi-objective genetic algorithm, taking the thickness and chamfer angles of the upper and lower ends as design variables, and the stress on the inner side of the casing wall and the axial force of the compressed rubber packer as optimization objectives. Besides that, the anti-shoulder extrusion variables are also introduced as constraints to prevent shoulder extrusion. Ultimately, the cross-sectional shape of the rubber packer with a smaller-thickness and larger-angle upper end, and a larger-thickness and smaller-angle lower end can be obtained. The result to emerge from the test in this paper is that the pipe pressure that can be sealed by the optimized rubber packer structure is 25.61% higher than that before optimization. The anti-shoulder extrusion variable and the asymmetric cross-sectional shape of the rubber packer proposed in this paper shed new light on the finite element simulation of rubber and the research on similar seals.

A Multiple Cross-Sectional Shape Optimization Method for Automotive Body Frames

2005 ◽  
Vol 127 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Masataka Yoshimura ◽  
Shinji Nishiwaki ◽  
Kazuhiro Izui
Keyword(s):  
Optimization Problem ◽  
Optimization Method ◽  
Continuous Variables ◽  
Cross Sectional ◽  
Automotive Body ◽  
Generating Method ◽  
Metal Sheets ◽  
Discrete Design Variables ◽  
The Cross ◽  
Sectional Shape

Automotive body frames, which profoundly affect automotive performance such as crashworthiness, are generally formed using pressed metal sheets, and the assembled cross-sectional shapes govern the frame characteristics. This paper proposes a cross-sectional shape generating method for achieving the cross-sectional properties assigned by design engineers. The cross-sectional shape-generating problem for pressed metal sheets is formulated as a multiobjective optimization problem that involves a marriage of continuous variables, such as shape dimensions, and discrete design variables, such as types of material and their thicknesses. Genetic algorithms are applied to solve the optimization problem.

scholarly journals Hair Structures Affecting Hair Appearance

Cosmetics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 43 ◽  
Author(s):  
Nagase
Keyword(s):  
Light Scattering ◽  
Total Reflection ◽  
Hair Length ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Factors Affecting ◽  
Hair Fiber ◽  
The Cross ◽  
Sectional Shape ◽  
Multiple Fibers

Optical factors affecting hair appearance are reviewed based on hair structures from macroscopic to microscopic viewpoints. Hair appearance is the result of optical events, such as reflection, refraction, scattering, and absorption. The effects of hair structures on such optical events are summarized and structural conditions for hair appearance are considered. Hair structures are classified into the following: the alignment of multiple hair fibers, the cross-sectional shape of the hair fiber, and the microstructures of hair fiber (cuticle, cortex, and medulla). The alignment of multiple hair fibers is easily affected by the existence of meandering fibers and their alignment along hair length becomes less-synchronized. The less-synchronized orientation of multiple fibers causes the broadening of the apparent reflection and luster-less dull impression. The cross-sectional shape of hair fiber affects light reflection behavior. Hair fibers with elliptical cross-section show glittering colored light based on total reflection in the hair. The scaly structures of cuticles at the surface of hair are often uplifted and cause light scattering, and then affect hair luster. The porous structure of the cortex and medulla in hair fiber can cause light scattering and affect hair luster and color. The above phenomena suggest that important factors for hair appearance are the alignment of multiple hair fibers, appropriate cross-sectional shape, ordered scaly structure, and pore-less internal structure.

Variation of the yarn cross-section in fabric

2012 ◽  
Vol 82 (7) ◽  
pp. 719-724 ◽  
Author(s):  
Raziye Befru Turan ◽  
Ayşe Okur
Keyword(s):  
Cross Section ◽  
Structural Parameters ◽  
Size Variation ◽  
Structural Factors ◽  
Cross Sectional ◽  
The Cross ◽  
Sectional Shape ◽  
Flattening Ratio ◽  
Shape And Size

The aim of this study is to investigate the cross-sectional shape and size variation of the yarn in fabric depending on the structural parameters of fabric. For this reason, the dimensions of the yarns that are in the different regions of the weave unit have been determined by achieving the cross-sectional images of the fabrics, which were woven with different weave types and at different weft settings. The variation in the cross-section of the yarn has been evaluated by using the flattening ratio. Consequently, it has been observed that the structural factors which determine the geometry of the fabric, such as weave type and setting, affect the cross-sectional properties of the yarn along the yarn path.

On the cross-sectional shape of the cellulose crystallites in the tunicate Halocynthia papillosa

1990 ◽  
Vol 48 (3) ◽  
pp. 566-567
Author(s):  
J.-F. Revol ◽  
Y. Van Daele ◽  
F. Gaill
Keyword(s):  
Contrast Imaging ◽  
Animal Kingdom ◽  
Bright Field ◽  
Field Mode ◽  
Cross Sectional ◽  
Ultrathin Sections ◽  
The Cross ◽  
Sectional Shape ◽  
Valonia Ventricosa ◽  
C Nmr

The only form of cellulose which could unequivocally be ascribed to the animal kingdom is the tunicin that occurs in the tests of the tunicates. Recently, high-resolution solid-state l3C NMR revealed that tunicin belongs to the Iβ form of cellulose as opposed to the Iα form found in Valonia and bacterial celluloses. The high perfection of the tunicin crystallites led us to study its crosssectional shape and to compare it with the shape of those in Valonia ventricosa (V.v.), the goal being to relate the cross-section of cellulose crystallites with the two allomorphs Iα and Iβ.In the present work the source of tunicin was the test of the ascidian Halocvnthia papillosa (H.p.). Diffraction contrast imaging in the bright field mode was applied on ultrathin sections of the V.v. cell wall and H.p. test with cellulose crystallites perpendicular to the plane of the sections. The electron microscope, a Philips 400T, was operated at 120 kV in a low intensity beam condition.

scholarly journals Optimization of the cross-sectional shape of the belts of trihedral lattice supports

2019 ◽  
Vol 7 (4) ◽  
pp. 5-8
Author(s):  
Linar Sabitov ◽  
Ilnar Baderddinov ◽  
Anton Chepurnenko
Keyword(s):  
Objective Function ◽  
Nonlinear Optimization ◽  
Cross Section ◽  
Optimization Methods ◽  
Cross Sectional ◽  
Maximum Value ◽  
Axial Moment ◽  
The Cross ◽  
Nonlinear Optimization Methods ◽  
Sectional Shape

The article considers the problem of optimizing the geometric parameters of the cross section of the belts of a trihedral lattice support in the shape of a pentagon. The axial moment of inertia is taken as the objective function. Relations are found between the dimensions of the pentagonal cross section at which the objective function takes the maximum value. We introduce restrictions on the constancy of the consumption of material, as well as the condition of equal stability. The solution is performed using nonlinear optimization methods in the Matlab environment.

A fast multiobjective optimization approach to S-duct scoop inlets design with both inflow and outflow

2018 ◽  
Vol 233 (9) ◽  
pp. 3381-3394
Author(s):  
Lifang Zeng ◽  
Dingyi Pan ◽  
Shangjun Ye ◽  
Xueming Shao
Keyword(s):  
Multiobjective Optimization ◽  
Total Pressure ◽  
Optimization Method ◽  
Navier Stokes ◽  
Integral Model ◽  
Optimization Approach ◽  
Navier Stokes Equation ◽  
Cross Sectional ◽  
Design Variables ◽  
Computational Fluid Dynamics Analysis

A fast multiobjective optimization method for S-duct scoop inlets considering both inflow and outflow is developed and validated. To reduce computation consumption of optimization, a simplified efficient model is proposed, in which only inflow region is simulated. Inlet pressure boundary condition of the efficient model is specified by solving an integral model with both inflow and outflow. An automated optimization system integrating the computational fluid dynamics analysis, nonuniform rational B-spline geometric representation technique, and nondominated sorting genetic algorithm II is developed to minimize the total pressure loss and distortion at the exit of diffuser. Flow field is numerically simulated by solving the Reynolds-averaged Navier–Stokes equation coupled with k–ω shear stress transport turbulence model, and results are validated to agree well with previous experiment. S-duct centreline shape and cross-sectional area distribution are parameterized as the design variables. By analyzing the results of a suggested optimal inlet chosen from the obtained Pareto front, total pressure recovery has increased from 97% to 97.4%, and total pressure distortion DC60 has decreased by 0.0477 (21.7% of the origin) at designed Mach number 0.7. The simplified efficient model has been validated to be reliable, and by which the time cost for the optimization project has been reduced by 70%.

Numerical study for the improvement of bead spreading architecture with modified nozzle geometries in additive manufacturing of polymers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Easir Arafat Papon ◽  
Anwarul Haque ◽  
Muhammad Ali Rob Sharif
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
3D Printing ◽  
Cross Section ◽  
Nozzle Exit ◽  
Cross Sectional ◽  
Content Type ◽  
The Cross ◽  
Viscous Polymer ◽  
Sectional Shape

Purpose This paper aims to develop a numerical model of bead spreading architecture of a viscous polymer in fused filament fabrication (FFF) process with different nozzle geometry. This paper also focuses on the manufacturing feasibility of the nozzles and 3D printing of the molten beads using the developed nozzles. Design/methodology/approach The flow of a highly viscous polymer from a nozzle, the melt expansion in free space and the deposition of the melt on a moving platform are captured using the FLUENT volume of fluid (VOF) method based computational fluid dynamics code. The free surface motion of the material is captured in VOF, which is governed by the hydrodynamics of the two-phase flow. The phases involved in the numerical model are liquid polymer and air. A laminar, non-Newtonian and non-isothermal flow is assumed. Under such assumptions, the spreading characteristic of the polymer is simulated with different nozzle-exit geometries. The governing equations are solved on a regular stationary grid following a transient algorithm, where the boundary between the polymer and the air is tracked by piecewise linear interface construction (PLIC) to reconstruct the free surface. The prototype nozzles were also manufactured, and the deposition of the molten beads on a flatbed was performed using a commercial 3D printer. The deposited bead cross-sections were examined through optical microscopic examination, and the cross-sectional profiles were compared with those obtained in the numerical simulations. Findings The numerical model successfully predicted the spreading characteristics and the cross-sectional shape of the extruded bead. The cross-sectional shape of the bead varied from elliptical (with circular nozzle) to trapezoidal (with square and star nozzles) where the top and bottom surfaces are significantly flattened (which is desirable to reduce the void spaces in the cross-section). The numerical model yielded a good approximation of the bead cross-section, capturing most of the geometric features of the bead with a reasonable qualitative agreement compared to the experiment. The quantitative comparison of the cross-sectional profiles against experimental observation also indicated a favorable agreement. The significant improvement observed in the bead cross-section with the square and star nozzles is the flattening of the surfaces. Originality/value The developed numerical algorithm attempts to address the fundamental challenge of voids and bonding in the FFF process. It presents a new approach to increase the inter-bead bonding and reduce the inter-bead voids in 3D printing of polymers by modifying the bead cross-sectional shape through the modification of nozzle exit-geometry. The change in bead cross-sectional shape from elliptical (circular) to trapezoidal (square and star) cross-section is supposed to increase the contact surface area and inter-bead bonding while in contact with adjacent beads.

Discrete sizing, cross-sectional shape, topology optimization, and material selection of a framed automotive body

2021 ◽  
pp. 095440702110626
Author(s):  
Chao Ma
Keyword(s):  
Weight Reduction ◽  
Material Selection ◽  
Extreme Points ◽  
Optimization Method ◽  
Test Problems ◽  
Manufacturing Cost ◽  
Cross Sectional ◽  
Automotive Body ◽  
Discrete Design Variables ◽  
Sectional Shape

This study proposed a discrete structural optimization method for a framed automotive body. Up to four types of discrete design variables are considered simultaneously, that is, the sizing, cross-sectional shape, topology, and material variables. Firstly, to solve the nonconvex and nonlinear optimization problem, the original non-dominated sorting genetic algorithm, the third version (NSGA-III), is adapted. An improved extreme points identification scheme and a new mutation operator are proposed to stabilize the normalization of the population and accommodate the manufacturing constraints, respectively. Two test problems demonstrate that the modified NSGA-III can handle continuous and discontinuous multiple objective optimization. Subsequently, the classical 10-bar truss is used to illustrate the proposed method. A weight reduction of 4.5 kg is achieved as compared to previous optimal designs in the literature. Finally, a framed automotive body is optimized for maximizing the first order natural frequency and minimizing the total mass, the maximum stresses and the maximum displacements in different load cases and the manufacturing cost. The results obtained by different optimization procedures are presented and discussed. The results demonstrate the feasibility and effectiveness of the proposed method. A weight reduction of 17.59% is achieved while other structural performances satisfy the design requirements.

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