• Title, Summary, Keyword: Surface geometry

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Surface Geometry of o-Diiodobenzene Adsorbed on Silver Colloid Surface (은 콜로이드 표면에 흡착된 o-Diiodobenzene의 흡착양식)

  • Jung Sang Suh
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.169-173
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    • 1992
  • The surface geometry of o-diiodobenzene (ODIB) adsorbed on silver colloid surfaces has been studied. This molecule is standing up on 1 day old colloid surfaces, while it is lying down or standing up on 1 month old colloid surfaces. The surface geometry of ODIB is affected by the atomic scale surface roughness of colloid used. The SERS intensity of ODIB for lying down geometry is much more strong than that for standing up. This may be mainly due to that the distance from surface to the center of the molecule in lying down geometry is shorter than that in standing up.

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Analysis on the Surface Accuracy in according to Geometry of End Mill (엔드밀의 형상에 따른 가공정밀도 해석)

  • 고성림;이상규;김용현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1001-1004
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    • 2000
  • As tools for machining precision components, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing diameter, liable to deflect and induce deterioration of surface roughness. Tool geometry parameters and cutting process have complex relations with each other. So, It is hard to determine hew to select optimal tool geometry. So, to improve the stiffness, relationship between cutting process and tool geometry must be studied. In this study, relations between grinding wheel geometry, setting condition and tool geometry are revealed. For the purpose of studying relations between each parameter, the equivalent diameter of tool has been calculated assuming tool as a simple beam. By the various cutting simulations and experiments, tool geometry and cutting process has been studied.

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New Geometric modeling method: reconstruction of surface using Reverse Engineering techniques

  • Jihan Seo
    • Proceedings of the Safety Management and Science Conference
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    • pp.565-574
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    • 1999
  • In reverse engineering area, it is rapidly developing reconstruction of surfaces from scanning or digitizing data, but geometric models of existing objects unavailable many industries. This paper describes new methodology of reverse engineering area, good strategies and important algorithms in reverse engineering area. Furthermore, proposing reconstruction of surface technique is presented. A method find base geometry and blending surface between them. Each based geometry is divided by triangular patch which are compared their normal vector for face grouping. Each group is categorized analytical surface such as a part of the cylinder, the sphere, the cone, and the plane that mean each based geometry surface. And then, each based geometry surface is implemented infinitive surface. Infinitive average surface's intersections are trimmed boundary representation model reconstruction. This method has several benefits such as the time efficiency and automatic functional modeling system in reverse engineering. Especially, it can be applied 3D scanner and 3D copier.

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The Study on Reconstruction of Composite Surfaces by Reverse Engineering Techniques (Reverse Engineering 기술을 적용한 복합면의 재구성 정보 추출을 위한 연구)

  • Seo, Ji-Han;Lee, Hong-Chul;Shone, Young-Tea;Park, Se-Hyung
    • IE interfaces
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    • v.12 no.2
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    • pp.205-209
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    • 1999
  • In reverse engineering area, the reconstruction of surfaces from scanned or digitized data is being developed, but geometric model of existing objects is not available in industries. This paper presents the new approach to the reconstruction of surface technique. A proposed methodology finds base geometry and blends surface between them. Each based geometry is divided by tri-angular patches which are compared with their normal vector for face grouping. Each group is categorized analytical surface such as a part of cylinder, sphere and cone, and plane shapes to represent the based geometry surface. And then, each based geometry surface is implemented to the infinitive surface. Infinitive surface's intersections are trimmed by boundary representation model reconstruction. This method has several benefits such as time efficiency and automatic functional modeling system in reverse engineering. Especially, it can be directly applied 3D fax and 3D copier.

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Determination of active failure surface geometry for cohesionless backfills

  • Altunbas, Adlen;Soltanbeigi, Behzad;Cinicioglu, Ozer
    • Geomechanics and Engineering
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    • v.12 no.6
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    • pp.983-1001
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    • 2017
  • The extent by which economy and safety concerns can be addressed in earth retaining structure design depends on the accuracy of the assumed failure surface. Accordingly, this study attempts to investigate and quantify mechanical backfill properties that control failure surface geometry of cohesionless backfills at the active state for translational mode of wall movements. For this purpose, a small scale 1 g physical model study was conducted. The experimental setup simulated the conditions of a backfill behind a laterally translating vertical retaining wall in plane strain conditions. To monitor the influence of dilative behavior on failure surface geometry, model tests were conducted on backfills with different densities corresponding to different dilation angles. Failure surface geometries were identified using particle image velocimetry (PIV) method. Friction and dilation angles of the backfill are calculated as functions of failure stress state and relative density of the backfill using a well-known empirical equation, making it possible to quantify the influence of dilation angle on failure surface geometry. As a result, an empirical equation is proposed to predict active failure surface geometry for cohesionless backfills based on peak dilatancy angle. It is shown that the failure surface geometries calculated using the proposed equation are in good agreement with the identified failure surfaces.

Development of Geometry Design S/W using Analysis on Machining Characterization considering EndMill Geometry (엔드밀 형상에 따른 가공특성 분석을 이용한 형상설계 S/W 개발)

  • 한창규;고성림;유중학;서천석;김경배
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.111-117
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    • 2004
  • The tool geometry parameters and cutting process have complex relationships. Until now, various cutting test were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process. In high speed machining. Using various tools with different geometry, relationships between tool geometry parameter (rake angle, clearance angle, length of cutter) and cutting process (cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining and developed tool geometry design S/W.

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Effects of Surface Geometry on Polyelectrolyte Adsorption

  • Park, Young-G.;Kim, Key-Seek;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.17 no.2
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    • pp.149-156
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    • 2000
  • For the adsorption of polyelectrolyte at the surface of polyacrylamide gel particle, preferential adsorption of the large polyelectrolyte such as DNA is governed by the surface area of an adsorbent. The adsorption equilibrium constant can be varied by surface geometry of porous polymer, and it can be described as a function of ionic strength and surface area. Physical parameters affecting the adsorption were estimated using the theoretical governing equation of polyelectrolyte which electrophoretically moved along the column, and geometrical surface area was estimated by Waldman-Mayer's physical model. The separation of polyelectrolytes was studied using the physical parameters estimated by ionic strength and surface geometry.

Addendum Surface Modeling in Draw Die Design for Stamping Automotive Panels (자동차 프레스 패널 성형을 위한 드로 금형의 어덴덤 곡면 모델링)

  • Chung, Yunchan
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.22 no.6
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    • pp.1018-1024
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    • 2013
  • In the process of draw die design for stamping automotive press panels, the addendum surfaces generated in metal forming simulation software cannot be used in downstream processes such as machining and making draw dies because simulation tools use simple discrete models for the surface geometry. The downstream processes require more precise and continuous geometric models such as NURBS surfaces. Generally, automotive die engineers manually regenerate the addendum surface geometry using the discrete model. This paper presents an automated geometric modeling process for generating addendum surfaces using draft surface models. The design parameters of the section curve for the addendum surfaces are extracted automatically from the draft geometry. Using the extracted design parameters, smooth addendum surfaces are generated automatically as NURBS surfaces. The generated surfaces are $G^1$ continuous with the part surface and the binder surface, and can be used in downstream processes.

Parametric surface and properties defined on parallelogrammic domain

  • Fan, Shuqian;Zou, Jinsong;Shi, Mingquan
    • Journal of Computational Design and Engineering
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    • v.1 no.1
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    • pp.27-36
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    • 2014
  • Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

A Study on the Design of Endmill Geometry in High Speed Machining (고속가공용 엔드밀의 형상설계에 관한 연구(2))

  • 고성림;배승민;김경배;서천석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.19-22
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    • 1997
  • The objective of this research is to use an analytical and experimental approach to develop optimal tool geometry for high speed machining. The tool geometry parameters and cutting process have complex relationships. Until now, numerous cutting tests were needed to acquire optimal design of endmill for the purpose of high speed machining, dut to the insufficient knowledge about process in high speed machining. In order to improve the cutting ability of endmill, a model for optimal cutter shape was developed to minimize resultant cutting force by combing cutting force and wear test and surface roughness test from optimized and conventional cutter with the same cutting condition. Using various tools with different geometry, relationships between the tool geometry parameter, rake angle, clearance angle, lengh of cutter have been stuied.

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