Skeleton-Section Template Parameterization for Shape Optimization

A technique based on a skeleton-section template for parameterizing finite element (FE) models is reported and applied to shape optimization of thin-walled beam components. The template consists of a skeletal curve and a set of cross-sectional profiles. The skeletal curve can be used to derive global model variations, while the cross section is designed to obtain local deformations of the given shape. A mesh deformation method based on the radial basis functions (RBF) interpolation is employed to derive the shape variations. Specifically, the skeleton-embedding space and an anisotropic distance metric are introduced to improve the RBF deformation method. To validate the applicability of the proposed template-based parameterization technique to general shape optimization frameworks, two proof-of-concept numerical studies pertaining to crashworthiness design of an S-shaped frame were implemented. The first case study focused on global deformations with the skeletal curve, and the second treated the cross-sectional profiles as design parameters to derive local reinforcements on the model. Both studies showed the efficiency of the proposed method in generation of quality shape variants for optimization. From the numerical results, considerable amount of improvements in crashworthiness performances of the S-shaped frame were observed as measured by the peak crushing force (PCF) and the energy absorption. We conclude that the proposed template-based parameterization technique is suitable for shape optimization tasks.

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Positioning Effect on Free Convection with an Elliptical Plate Placed in a Circular Enclosure

Advanced Science Engineering and Medicine ◽

10.1166/asem.2020.2668 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1054-1062

Author(s):

Parth Patpatiya ◽

Soumya ◽

Bhavya Shaan ◽

Bhavana Yadav

Keyword(s):

Heat Transfer ◽

Aspect Ratio ◽

The Body ◽

Elliptical Plate ◽

Numerical Studies ◽

First Case ◽

Varied Temperature ◽

Laminar Natural Convection ◽

The Given ◽

Plate System

In this analysis we have examined the process of the steady state laminar natural convection around heated elliptical plate with Rayleigh number 10^6 positioned inside a circular enclosure. The purpose of the numerical analysis is to analyze the behavior of isotherms, streamlines and heat transfer rate in enclosure plate system due to the variation in the position of elliptical plate (r/D =0.00, 0.05, and 0.2) and aspect ratio, where the given diameter of the enclosure is D and r is the distance between the centre of elliptical plate and centre of circle. Elliptical plate is inclined at different angles and results are summed up in relative manner. There are two cases, in first case aspect ratio a/D and b/D is varied and D is kept constant, whereas in second case aspect ratio a/D and b/D is kept constant and D is varied. Temperature difference between the enclosure and the inner body (i.e., temperature of inner body is kept high as compared to the enclosure) is maintained. Two dimensional study is followed by considering air as a fluid in enclosure. The effects of the Heat Transfer and Flow of Fluid are analyzed by the streamlines and isotherms plotted for the body placed inside enclosure. Value of local Nusselt number (Nu) is also plotted along the wall of elliptical plate and along the surface of the circular enclosure. For every aspect ratio isotherms and streamlines had been plotted. This work has been validated with various other numerical studies and was in good conciliation.

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Design Innovation Size and Shape Optimization of a 1.0mm Multifunctional Forceps-Scissors Surgical Instrument

Journal of Medical Devices ◽

10.1115/1.2885141 ◽

2008 ◽

Vol 2 (1) ◽

Cited By ~ 8

Author(s):

Milton E. Aguirre ◽

Mary Frecker

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Shape Optimization ◽

Optimization Problems ◽

Cross Sectional Area ◽

Sectional Area ◽

Element Analysis ◽

Cross Sectional ◽

Size And Shape ◽

The Cross

A size and shape optimization routine is developed for a 1.0mm diameter multifunctional instrument for minimally invasive surgery. The instrument is a compliant mechanism capable of both grasping and cutting. Multifunctional instruments are expected to be beneficial in the operating room because of their ability to perform multiple surgical tasks, thereby decreasing the total number of instrument exchanges in a single procedure. With fewer instrument exchanges, the risk of inadvertent tissue trauma as well as overall surgical time and costs are reduced. The focus of this paper is to investigate the performance effects of allowing the cross-sectional area along the length of the device to vary. This investigation is accomplished by defining various cross-sectional segments in terms of parametric variables and optimizing the dimensions of the instrument to provide a sufficient opening of the forceps jaws while maintaining adequate cutting and grasping forces. Two optimization problems are considered. First, all parametric segments are set equal to one another to achieve size optimization. Second, each segment is allowed to vary independently, thereby achieving shape optimization. Large deformation finite element analysis and optimization are conducted using ANSYS®. Finally, prototypes are fabricated using wire EMD and experiments are conducted to evaluate the instrument performance. As a result of allowing the cross-sectional area to vary, i.e., conducting shape optimization, the forceps and scissors blocked forces increased by as much as 83.2% and 87%, respectively. During prototype evaluations, it is found that the finite element analysis predictions were within 10% of the measured tool performance. Therefore, for this application, it is concluded that performing shape optimization does significantly influence the performance of the instrument.

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Optimum Design of Internal Strain-Gage Balances: An Example of Three-Dimensional Shape Optimization

Journal of Mechanisms Transmissions and Automation in Design ◽

10.1115/1.3267448 ◽

1987 ◽

Vol 109 (2) ◽

pp. 257-262 ◽

Cited By ~ 2

Author(s):

J. W. Hou ◽

S. L. Twu

Keyword(s):

Shape Optimization ◽

Strain Gage ◽

Three Dimensional ◽

Design Procedure ◽

Internal Strain ◽

Main Body ◽

Cross Sectional ◽

Dimensional Shape ◽

The Cross ◽

Three Dimensional Shape

Internal strain-gage balances are often applied to measure the aerodynamic loads acting on the aircraft model in the wind-tunnel test. The balance system consists essentially of one main body and two shoulders elastically interconnected by multibar cages. Designing the cross-sectional geometry of such a multibar cage balance to improve the accuracy of load measurement is an important task for a balance engineer. The study presents an initial attempt to carry out such a design task in a systematic and automated manner. This is achieved by considering two aspects. One is to establish a mathematical model to analyze the stress distribution in the elastic cage and the other is to adopt a three-dimensional shape optimization scheme to design the cross-sectional geometry of the internal strain-gage balance. The design procedure has been completely automated in a computer program. Numerical examples shows that the proposed numerical scheme performs very well.

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Design of C-Frames Using Real-Coded Genetic Optimization Algorithms and NURBS

Volume 2: 19th Computers and Information in Engineering Conference ◽

10.1115/detc99/cie-9138 ◽

1999 ◽

Author(s):

Ashraf O. Nassef ◽

Hesham A. Hegazi ◽

Sayed M. Metwalli

Keyword(s):

Genetic Algorithms ◽

Cross Section ◽

Cross Sections ◽

Design Parameters ◽

Binary Representation ◽

Cross Sectional ◽

Search Spaces ◽

The Cross ◽

Sectional Shape ◽

Real Coded Genetic Algorithms

Abstract C-frames constitute a large portion of machine tools that are currently used in industry. Examples of these frames include drilling machines, presses, punching and stamping machines, clamps, hooks, etc. The design parameters of these frames include the dimensions of their cross-sections, which should be chosen to withstand the applied loads and minimize the element’s overall weight. Traditionally, the cross-section of C-frame belonged to a set of primitive shapes, which included I, T, trapezoidal and rectangular sections. This paper introduces a new methodology for designing the frame’s cross-section. The cross-sectional shape is represented using non-uniform rational B-Spline (NURBS) in order to give it a form of shape flexibility. A special form of genetic algorithms known as real-coded genetic algorithms is used to conduct the search for the design objectives. Real-coded genetic algorithms are known to outperform the simple binary representation genetic algorithms when dealing with continuous search spaces. The results showed that the optimal shape was a semi I/T-section with the material bulk related to the applied load.

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Development of multifunctional different cross-sectional shaped coaxial composite filaments for SMART textile applications

Textile Research Journal ◽

10.1177/0040517516663144 ◽

2016 ◽

Vol 87 (16) ◽

pp. 1991-2004 ◽

Cited By ~ 5

Author(s):

Ali Afzal ◽

Jean-Yves Drean ◽

Omar Harzallah ◽

Nabyl Khenoussi ◽

Sheraz Ahmad ◽

...

Keyword(s):

Pure Copper ◽

Resin Matrix ◽

Design Parameters ◽

Cross Sectional ◽

Smart Textile ◽

The Cross ◽

Sectional Surface ◽

Poly Ethylene ◽

Sectional Shape

The aim of this study is to design a spinneret that can be used efficiently for the manufacturing of coaxial composite filaments. Poly(ethylene terephthalate) was used as resin matrix with 99.9% pure copper filament as the core. The characterization of the polymer was done to determine polymer thermal and rheological properties. Multi-shaped coaxial composite filaments were obtained after successful laboratory-scale melt extrusion machine modification and spinneret development. The cross-sectional surface and shape were analyzed with a scanning electron microscope. Coaxial filaments having the cross-section including elliptical, triangular, rectangular and circular shapes were developed. The characterization of spinneret design and coaxial composite filaments were also reported. The effect of spinneret design parameters on the cross-sectional shape of the filament were analyzed.

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Development of Double Suction Volute Pump for High Efficiency

Volume 1B, Symposia: Fluid Machinery; Fluid Power; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Fundamental Issues and Perspectives in Fluid Mechanics ◽

10.1115/fedsm2013-16345 ◽

2013 ◽

Cited By ~ 2

Author(s):

Katsutoshi Kobayashi ◽

Isao Hagiya ◽

Hideki Akiniwa ◽

Hiroaki Yoda ◽

Daijirou Senba

Keyword(s):

Pressure Loss ◽

Total Pressure ◽

High Efficiency ◽

Flow Path ◽

Total Pressure Loss ◽

Design Parameters ◽

Pump Efficiency ◽

Cross Sectional ◽

Swirl Velocity ◽

The Cross

The double suction volute pump consists of three components: a double suction flow path in upstream, an impeller with five blades, and a double volute flow path in downstream. The double suction was designed to improve a flow on the inlet surface of impeller. A significantly high pre-swirl velocity and low pre-swirl velocity were observed in original double suction, however its high pre-swirl velocity was slowed down and its low pre-swirl velocity was speeded up in designed double suction. As a result, the designed double suction had a more uniform velocity distribution on the inlet surface of impeller. The impeller had twenty design parameters and those parameters were optimized by genetic algorithm (GA) to improve the impeller efficiency. A high total pressure loss was observed on the outlet surface of impeller and near the shroud wall of impeller meridian surface. On the other hand, its total pressure loss was decreased in optimized impeller, and the impeller efficiency increased by +0.7[%]. The cross-sectional surfaces, which were defined on a main streamwise curve of double volute, were designed to decrease a total pressure loss occurring inside double volute. In designed double volute, a secondary vortex on the cross-sectional surface was suppressed and a high circumferential velocity was decreased near the tongue and front edge of partition wall. As a result, the total pressure loss was decreased inside designed double volute. The hydraulic pump performance for designed pump, which consisted of the designed double suction, optimized impeller and designed double volute, was predicted by numerical simulation. Efficiencies in double suction, impeller and double volute were increased by 0.6[%], 0.4[%] and 1.1[%] respectively and the total improvement of pump efficiency was 1.9[%]. The designed pump was manufactured and its hydraulic performance was measured by experiment. The numerical results of pump efficiency agreed well with experimental ones. The efficiency of designed pump increased by 2.0[%] compared with that of original pump in experiment.

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Cross Analysis of Metal Foam Design Parameters for Achieving Desired Fluid Flow

Volume 6: Fluids and Thermal Systems; Advances for Process Industries, Parts A and B ◽

10.1115/imece2011-64916 ◽

2011 ◽

Cited By ~ 2

Author(s):

Timothy Hess ◽

Beshoy Morkos ◽

Mark Bowman ◽

Joshua D. Summers

Keyword(s):

Pore Size ◽

Metal Foam ◽

Air Flow ◽

Maximum Flow ◽

Design Parameters ◽

Constant Density ◽

Cross Sectional ◽

Manufacturing Method ◽

Flow Through ◽

The Cross

This paper presents an experimental study of air flow through open cell metal foams for use as a thermal energy dissipating system. The goal of this paper is to identify the optimum configuration of metal foam design parameters for maximum flow. Four foam blocks were used in the study, representing a range of design parameters: material (copper or aluminum), pore size (5–10 pores per inch), and relative density (ε = 0.875–0.952). The effects of pore size were isolated by comparing air flow through three aluminum foam blocks with constant density and varied pore size. A series of wind tunnel tests were performed to measure the velocity of air flowing through the foam as a function of the free stream air velocity, ranging from 0 to 17.4 mph (7.5 m/s). Results indicated smaller pore sizes and larger densities decreased the amount of airflow through the foam. However, one foam sample produced results that did not fit this trend. Further investigation found this was likely due to the differences in the cross-sectional geometry of the foam ligaments. The ligament geometry, affected by density and manufacturing method, was not constant and not initially considered as a variable of interest. The cross-section shape of the ligaments was found to vary from a rounded triangular shape to a triangle shape with concave surfaces, increasing the amount of drag in the airflow through the sample.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160388 ◽

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.

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