• Title/Summary/Keyword: Geometrical Characteristics

Search Result 776, Processing Time 0.025 seconds

A Study on the Weldline Movement and Formability of Tailored Blanks in Square Cup Drawing (사각통 드로잉시 테일러드 블랭크의 용접선이동 및 성형성에 관한 연구)

  • ;Hisashi Hayashi;Matsuo Usuda
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1997.03a
    • /
    • pp.42-45
    • /
    • 1997
  • Weldline movement of tailored blanks originates from two sources, primary and secondary. Primary movement occurs by geometrical reason, that is, just scratched lines on the no-weld blanks move during drawing to be fitted to geometrical change. Secondary movement is induced by the characteristics of tailored blanks itself. The primary movement was mainly dependent on the weldline location and not affected by the type of material. The secondary movement caused by laser welding and/or small strength difference in this study was not dominant compared with primary movement. The formability of tailored blanks always inferior to those of original blanks. This is due to the existence of hardened weld bead. The closer a weldline is to punch corner where drawing is most active, the worse its formability becomes. This is because the weldline prohibits the drawing process. It was confirmed by measuring diagonal length at the blank corner. The mode of fracture was changed form wall break to draw break when the weldling was close to the punch corner.

  • PDF

A Study on the Production Mechanisms of Residual Stress in Welded T-joint of Steel Pipe Member (T형 강관 용접 이음부의 잔류응력 생성기구에 관한 연구)

  • 장경호;장갑철;경장현;이은택
    • Journal of Welding and Joining
    • /
    • v.21 no.6
    • /
    • pp.40-45
    • /
    • 2003
  • Steel members have advantages of resisting torsion and axial compression. In design, residual stresses at the welded joint of T-shape steel pipes are one of the most important points to be considered. In this paper, characteristics of residual stresses of welded joints are clarified by carrying out 3D non-steady heat conduction analysis and 3D thermal elastic-plastic FE-analysis. According to the results, the production mechanism of residual stresses at the welded joint of T-shape steel pipe is clarified. In this paper, circumferential stresses depended on thermal histories but axial and radial stresses were more dependent on geometrical shape than thermal histories. Residual stresses in the axial direction on the lower part of pipe member were tensile, controlled by geometrical shape. However, in case of middle part, residual stresses in all the directions were controlled by thermal histories.

A New Digital Watermarking for Architectural Design Drawing Using LINES and ARCs Based on Vertex (건축설계도면상에서 꼭지점에 기반한 LINE과 ARC를 이용한 디지털 워터마킹)

  • Jang, Bong-Ju;Moon, Kwang-Seok;Young Huh;Kwon, Ki-Ryong
    • Proceedings of the IEEK Conference
    • /
    • 2003.11b
    • /
    • pp.247-250
    • /
    • 2003
  • This paper proposed to digital watermarking technique for architectural drawing using LINES and ARCs based on vertex in CAD system to prevent infringement of copyright from unlawfulness reproductions and distribution. After extract LINES and ARCs from designed drawing, we embed watermarks using adaptive algorithm in each characteristics. Watermarks robust to various attacks like as geometrical transformation as being embedded in LINE's length and ARC's angle information. Also, the proposed method satisfies enough transparency about watermarked drawing because have suitable embedding strength to each component. By experimental result, we confirmed robustness and invisibility of embedded watermarks in several conversions of architectural design drawing.

  • PDF

Adaptive Digital Watermarking for Copyright Protection of CAD Data

  • Kwon Ki-Ryong;Koo Bon-Ho;Kim Ji-Hong
    • Journal of Korea Multimedia Society
    • /
    • v.9 no.6
    • /
    • pp.709-719
    • /
    • 2006
  • To protect against unlawful reproductions and distribution, the current paper proposes a digital watermarking technique for architectural drawings produced using a CAD system. First, the POLYLINEs are extracted from the drawing; then, an adaptive algorithm is used to embed a watermark in the characteristics of each POLYLINE. Next, the CIRCLEs are embedded using an adaptive watermarking algorithm related to the radius of circle from drawing. The proposed watermarking scheme is robust to various attacks, such as the geometrical transformation. Additionally, the proposed method satisfies the requirement of transparency for CAD program. It used AutoCAD 2002, which is commonly used as a CAD program for experiments. Experimental results confirmed the robustness and invisibility of the embedded watermarks in several conversions of an architectural drawing.

  • PDF

Dynamic Analysis of a Geometrical Non-Linear Plate Using the Continuous-Time System Identification

  • Lim, Jae-Hoon;Choi, Yeon-Sun
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.11
    • /
    • pp.1813-1822
    • /
    • 2006
  • The dynamic analysis of a plate with non-linearity due to large deformation was investigated in this study. There have been many theoretical and numerical analyses of the non-linear dynamic behavior of plates examining theoretically or numerically. The problem is how correctly an analytical model can represent the dynamic characteristics of the actual system. To address the issue, the continuous-time system identification technique was used to generate non-linear models, for stiffness and damping terms, and to explain the observed behaviors with single mode assumption after comparing experimental results with the numerical results of a linear plate model.

Computer Vision System for Automatic Grading of Ginseng - Development of Image Processing Algorithms - (인삼선별의 자동화를 위한 컴퓨터 시각장치 - 등급 자동판정을 위한 영상처리 알고리즘 개발 -)

  • 김철수;이중용
    • Journal of Biosystems Engineering
    • /
    • v.22 no.2
    • /
    • pp.227-236
    • /
    • 1997
  • Manual grading and sorting of red-ginsengs are inherently unreliable due to its subjective nature. A computerized technique based on optical and geometrical characteristics was studied for the objective quality evalution. Spectral reflectance of three categories of red-ginsengs - "Chunsam", "Chisam", "Yangsam" - were measured and analyzed. Variation of reflectance among parts of a single ginseng was more significant than variation among the quality categories of ginsengs. A PC-based image processing algorithm was developed to extract geometrical features such as length and thickness of body, length and number of roots, position of head and branch point, etc. The algorithm consisted of image segmentation, calculation of Euclidean distance, skeletonization and feature extraction. Performance of the algorithm was evaluated using sample ginseng images and found to be mostly sussessful.

  • PDF

Fuzzy control for geometrically nonlinear vibration of piezoelectric flexible plates

  • Xu, Yalan;Chen, Jianjun
    • Structural Engineering and Mechanics
    • /
    • v.43 no.2
    • /
    • pp.163-177
    • /
    • 2012
  • This paper presents a LMI(linear matrix inequality)-based fuzzy approach of modeling and active vibration control of geometrically nonlinear flexible plates with piezoelectric materials as actuators and sensors. The large-amplitude vibration characteristics and dynamic partial differential equation of a piezoelectric flexible rectangular thin plate structure are obtained by using generalized Fourier series and numerical integral. Takagi-Sugeno (T-S) fuzzy model is employed to approximate the nonlinear structural system, which combines the fuzzy inference rule with the local linear state space model. A robust fuzzy dynamic output feedback control law based on the T-S fuzzy model is designed by the parallel distributed compensation (PDC) technique, and stability analysis and disturbance rejection problems are guaranteed by LMI method. The simulation result shows that the fuzzy dynamic output feedback controller based on a two-rule T-S fuzzy model performs well, and the vibration of plate structure with geometrical nonlinearity is suppressed, which is less complex in computation and can be practically implemented.

Analysis of Stripline Structure(Resonator) in LTCC System (LTCC System 에서의 Stripline 구조 특성 연구)

  • 유찬세;이우성;강남기;박종철
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.9 no.3
    • /
    • pp.13-17
    • /
    • 2002
  • In ceramic systems, many components including embedded passives and TRL(transmission line) are used for composition of 3-dimensional circuit. So the exact analysis on this components must be performed. As for the TRL's, material properties including electrical conductivity of metal, loss factor and effective dielectric constant of dielectric material and geometrical factors like roughness of surface, vias, dimension of stripline structure have a large effect on the charactersistics of transmission lines. In this research, effect of material and geometrical factors on the characteristics of stripline structure is analyzed and quantified by simulation and measurement.

  • PDF

Ultimate behavior of reinforced concrete cooling tower: Evaluation and comparison of design guidelines

  • Noh, Hyuk-Chun;Choi, Chang-Koon
    • Structural Engineering and Mechanics
    • /
    • v.22 no.2
    • /
    • pp.223-240
    • /
    • 2006
  • Taking into account the geometrical and material nonlinearities, an ultimate behavior of reinforced concrete cooling tower shell in hyperbolic configuration is presented. The design wind pressures suggested in the guidelines of the US (ACI) and Germany (VGB), with or without the effect of internal suction, are employed in the analysis to examine the qualitative and quantitative characteristics of each design wind pressure. The geometrical nonlinearity is incorporated by the Green-Lagrange strain tensor. The nonlinear features of concrete, such as the nonlinear stress-strain relation in compression, the tensile cracking with the smeared crack model, an effect of tension stiffening, are taken into account. The biaxial stress state in concrete is represented by an improved work-hardening plasticity model. From the perspective of quality of wind pressures, the two guidelines are determined as highly correlated each other. Through the extensive analysis on the Niederaussem cooling tower in Germany, not only the ultimate load is determined but also the mechanism of failure, distribution of cracks, damage processes, stress redistributions, and mean crack width are examined.

Stability of tow-steered curved panels with geometrical defects using higher order FSM

  • Fazilati, Jamshid
    • Steel and Composite Structures
    • /
    • v.28 no.1
    • /
    • pp.25-37
    • /
    • 2018
  • For the first time, the parametric instability characteristics of tow-steered variable stiffness composite laminated (VSCL) cylindrical panels is investigated using B-spline finite strip method (FSM). The panel is considered containing geometrical defects including cutout and delamination. The material properties are assumed to vary along the panel axial length of any lamina according to a linear fiber-orientation variation. A uniformly distributed inplane longitudinal loading varies harmoni-cally with time is considered. The instability load frequency regions corresponding to the assumed in-plane parametric load-ing is derived using the Bolotin's first order approximation through an energy approach. In order to demonstrate the capabili-ties of the developed formulation in predicting stability behavior of the thin-walled VSCL structures, some representative results are obtained and compared with those in the literature wherever available. It is shown that the B-spline FSM is a proper tool for extracting the stability boundaries of perforated delaminated VSCL panels.