• Title/Summary/Keyword: flat shape

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A STUDY OF THE MANDIBULAR CONDYLE SHAPE ON THE INDIVIDUALIZED CORRECTED TMJ TOMOGRAPH AND SUBMENTOVERTEX RADIOGRAPH (이하두정방사선사진과 개별화 단층방사선사진을 이용한 하악과두의 형태에 관한 연구)

  • 이상래
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.24 no.2
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    • pp.227-236
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    • 1994
  • The purpose of this study was to observe mandibular condyle shape in an asymptomatic population. In order to carry out this study, 96 temporomandibular joints in 48 adults(22 males, 26 females), who were asymptomatic for temporomandibular disturbances and had no history of prosthodontic or orthodontic treatments, were selected, and radiographed using the Sectograph(Denar Co., U.S.A.) for lateral and frontal individualized corrected TMJ tomograph and submentovertex radiograph. Mandibular condyles were classified morphologically, and measured medioateral and anteroposterior dimensions and condylar angulation. The obtained results were as follows. 1. In the classification of condyle shape on lateral tomographs, 94.8% were convex type and 5.2% were angled type. 2. In the classification of condyle shape on frontal tomographs, 45.3% were convex type, 32.0% were round type, 16.0% were flat type, and 6.7% were angled type. 3. In the classification of condyle shape on submentovertex radiographs, 34.5% were flat-convex type, 22.9% were flat-flat type, 20.8% were concave-convex type, 19.8% were convex-convex type, and 1.0% were concave-flat type and convex-flat type. Concave-concave type, convex-concave type, and flat-concave type were not observed. 4. The average mediolateral legth of the condyle was 19.3㎜ and the average anteroposterior length was 9.4㎜. The average angle between the long axis of condyle and the coronal plane made on submentovertex view was 19.6 degrees.

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A Study on the shape Design of the Forward Forming Region in Cross Rolling of Multi-Step Shaft (다단 샤프트 제조용 크로스롤 금형 선단부의 형상설계에 관한 연구)

  • 김익삼
    • Transactions of Materials Processing
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    • v.8 no.2
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    • pp.178-187
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    • 1999
  • The Cross rolling between flat jaws, as a kind of hot forging, is the forming method to make the axisymmetric multi-step shaft by its rotation and pressure between flat jaws which move in opposite direction. The purpose of this study is to propose the optimal geometric data for shape development of the forward forming region. All data described on this paper are quantified by experiment from initial shape design to final shape development. As the result, proper geometric data are proved that lenth of the first forming area in the forward forming region is 1.5 times larger than circumference of work-piece and the progress angle changes 3 times smoothly.

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Fault Tolerant Straight-Line Gaits of a Quadruped Robot with Feet of Flat Shape (평판 발을 가지는 사족 보행 로봇의 내고장성 걸음새)

  • Yang, Jung-Min;Kwak, Seong-Woo
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.2
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    • pp.141-148
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    • 2012
  • This paper proposes fault tolerant gaits of a quadruped robot with feet of flat shape. Fault tolerant gaits make it possible for a legged robot to continue static walking against a leg failure. In the previous researches, it was assumed that a legged robot had feet that have point contact with the surface. When the robot is endowed with feet having flat shape, fault tolerant gaits can show better performance compared with the former gaits, especially in terms of the stride length and gait stability. In this paper, fault tolerant gaits of a quadruped robot against a locked joint failure are addressed in straight-line motion and crab walking, respectively.

Numerical Analysis on Strength of Interior Flat Plate-Column Connections according to Column Section Shape (기둥 단면형상에 따른 플랫플레이트-기둥 접합부 강도에 관한 수치해석연구)

  • Kang Su Min;Kim Oak Jong;Lee Do Bum;Park Hong Gun;Chun Young Soo;Lee Hyun Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.291-294
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    • 2005
  • In the present study, a numerical analysis was performed for interior connections of continuous flat plate to analyze the effect of column section shape on the behavioral characteristics of the connections. For the purpose, a computer program for nonlinear FE analysis was developed, and the validity was verified. Through the parametric study, the variations of shear stress distribution around the connection were investigated. According to the result of numerical analysis, the column section shape has a serious effect on the behavior of the connections. As the length of the cross section of column in the direction of lateral load increases, the effective area and the shear strength at the sides providing the torsional resistance decrease considerably. Therefore the strength model for the flat plate-column connections should be modified by considering the effect of column section shape on the behavior of the connections.

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Effect of a Coil Shape on an Impulse Velocity of the Electromagnetic Welding (전자기 용접의 충돌 속도에 대한 코일 형상의 영향)

  • Park, H.;Lee, K.;Lee, J.;Lee, Y.;Kim, D.
    • Transactions of Materials Processing
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    • v.28 no.3
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    • pp.135-144
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    • 2019
  • Electromagnetic impulse welding (EMIW) is a type of solid state welding using the Lorentz force generated by interaction between the magnetic field of the coil and the current induced in the workpiece. Although many experimental studies have been investigated on the expansion and compression welding of tube using the EMIW process, studies on the EMIW process of lap joint between flat sheets are uncommon. Since the magnetic field enveloped inside the tube can be controlled with ease, the electromagnetic technique has been widely used for tube welding. Conversely, it is difficult to control the magnetic field in the flat sheet welding so as to obtain the required welding velocity. The current study analyzed the effects of coil shape on the impulse velocity for suitable flat one-turn coil for the EMIW of the flat sheets. The finite element (FE) multi-physics simulation involving magnetic and structural field of EMIW were conducted with the commercial software LS-DYNA to evaluate the several shape variables, viz., influence of various widths, thicknesses, gaps and standoff distances of the flat one-turn coil on the impulse velocity. To obtain maximum impulse velocity, the flat one-turn coil was designed based on the FE simulation results. The experiments were performed using an aluminum alloy 1050 sheets of 1.0mm thickness using the designed flat one-turn coil. Through the microscopic interfacial analysis of the welded specimens, the interfacial connectivity was observed to have no defects. In addition, the single lap joint tests were performed to evaluate the welding strength, and a fracture occurred in the base material. As a result, a flat one-turn coil was successfully designed to guarantee welding with bond strength equal to or greater than the base material strength.

Application of ICP(Iterative Closest Point) Algorithm for Optimized Registration of Object Surface and Unfolding Surface in Ship-Hull Plate Forming (선박 외판 성형에서 목적 형상과 전개 평판의 최적 정합을 위한 ICP(Iterative Closest Point) 알고리즘 적용)

  • Lee, Jang-Hyun;Yoon, Jong-Sung;Ryu, Cheol-Ho;Lee, Hwang-Beom
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.2
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    • pp.129-136
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    • 2009
  • Generally, curved surfaces of ship hull are deformed by flame bending (line heating), multi-press forming, and die-less forming method. The forming methods generate the required in-plane/bending strain or displacement on the flat plate to make the curved surface. Multi-press forming imposes the forced displacements on the flat plate by controlling the position of each pressing points based upon the shape difference between the unfolded flat plate and the curved object shape. The flat plate has been obtained from the unfolding system that is independent of the ship CAD. Apparently, the curved surface and the unfolded-flat surface are expressed by different coordinate systems. Therefore, one of the issues is to find a registration of the unfolded surface and the curved shape for the purpose of minimum amount of forming works by comparing the two surfaces. This paper presents an efficient algorithm to get an optimized registration of two different surfaces in the multi-press forming of ship hull plate forming. The algorithm is based upon the ICP (Iterative Closest Point) algorithm. The algorithm consists of two iterative procedures including a transformation matrix and the closest points to minimize the distance between the unfolded surface and curved surfaces. Thereby the algorithm allows the minimized forming works in ship-hull forming.

2D Lower Body Flat Pattern of the Women in Their Twenties Using 3D Scan Data (3차원 인체 형상을 이용한 20대 여성의 하반신 전개패턴에 관한 연구)

  • Yoon, Mi-Kyung;Nam, Yun-Ja;Choi, Kyeng-Mi
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.5 s.164
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    • pp.692-704
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    • 2007
  • Recently, Basic patterns with excellent body fitness and automation availability are required to be developed in order to automate the patterns of women's clothes. In this study, this reference points, reference lines and segments were fixed onto 3D scan data for the lower body the women in their twenties, they were directly spread out to be 2D flat pattern to facilitate development into the design of slacks adhered closely to the human body such as special and highly-functional clothes, and then slacks 2D pattern was developed for the purpose of seeking scientific approach to the development into basic form slacks and 3d emotional pattern. For conversion of 3D pattern into 2D flat pattern, reference points and segments were created by using Rapid Form of 3D shape analysis software, and triangle mesh of the body surface of the created shape was developed with Auto CAD 2005. The correspondence between slacks and human body was examined by the fixation of major reference lines. Specially, the wearing characteristics of slacks were considered by the fixation of side lines in consideration of posture. As a result of using the way of development to constantly maintain the length while 3D triangle mesh is converted into 2D flat mesh, the shape was shown to be excellently reproduced, and the area of flat pattern was increased compared to the shape of parting plane. Also, the sunk-in curve like the brief line of front crotch length needed a cutting line when it was closely adhered, when mesh was overlapped, and the pattern area was smaller compared to the actual shape.

Natural Frequency Maximization Using a Flat-top Emboss (윗면이 평평한 엠보스 형상을 이용한 고유 진동수 극대화)

  • 송경호;박윤식;박영진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.72-76
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    • 2003
  • Even though embossing is an effective SDM(Structural Dynamics Modification) technique, it is difficult to implement the method in fields owing to its geometric complexity. In this research low flat-top emboss shape, rather than general shape, is considered and a systematic procedure is derived in describing the emboss implementation procedure utilizing the fact that the emboss shape can be fully expressed only if the boundary elements are appropriately given. Best position to maximize natural frequencies is found using the procedure and usefulness of the suggested technique is illustrated.

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Analysis on the Depressing Force to the Cornea by Fitted Spherical Contact Lens (구면 콘택트렌즈의 피팅에 따른 각막 부착력 해석)

  • Kim, Dae Soo
    • Journal of Korean Ophthalmic Optics Society
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    • v.16 no.1
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    • pp.97-106
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    • 2011
  • Purpose: This review article was written to theoretically compare the depressing force (pressure, adhesion) to the cornea between when the spherical lenses were being tightly and flat fitted. Methods: Mathematical equations and their numerical solution programs (model) were formulated to calculate the depressing (adhesion) force to the cornea by both the tightly and flat fitted contact lenses. Based on this proposed model the effects of parameters characterizing a contact lens such as BCs, diameters, edge shape and corneal shape (ratio of long and short corneal axis, p) on the depressing force to the cornea were predicted/analyzed in both tightly and flat fitting regimes. Results: Corneal adhesion increased as the corneal p-value increased. Adhesion increase caused by the increased p-value was much larger in flat fitted case than in tight fitted one. Corneal adhesion reduced abruptly as the BC increased in flat fitting regimes while the adhesion rise was insignificant in tight fitting ones. Reduction in corneal adhesion due to lens-size increase was predicted to be insignificant in both tight and flat fitting regimes. Both the lens edge shape (edge angle) and thickness were relevant only in tight fitting regime. Corneal adhesion increased as the increased with tight-fitted lenses. As the thickness of tight fitted lenses increased, corneal adhesion inversely decreased. Conclusions: The two most significantly affecting the depressing force to cornea were found to be the degree of corneal bending toward the periphery and the BCs of lenses.