• Title/Summary/Keyword: Circular Plate

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Analysis of Anisotropic Circular Conical Shells with Free Supports (자유경계를 갖는 비등방성 원뿔형 쉘의 해석)

  • Son, Byung Jik;Baik, Han Sol;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.12 no.4 s.47
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    • pp.417-428
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    • 2000
  • In recent years, composite materials have been used in civil engineering as well as architecture, automobile, aerospace, shipping industries. Composite materials are composed of two or more different materials to produce desirable properties for structural strength. The shell structures have the advantage of more efficient load resistance due to its curved shape as compared to the plate structures. And the shell structures with composite materials have many advantages in strength, corrosion resistance, and weight reduction. The objective of this study is to analyze circular conical shells with shear deformation effects and to prove the advantage of composite materials. To solve differential equations of conical shells, this paper used finite difference method.

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Acoustic Emission Source Classification of Finite-width Plate with a Circular Hole Defect using k-Nearest Neighbor Algorithm (k-최근접 이웃 알고리즘을 이용한 원공결함을 갖는 유한 폭 판재의 음향방출 음원분류에 대한 연구)

  • Rhee, Zhang-Kyu;Oh, Jin-Soo
    • Journal of the Korea Safety Management & Science
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    • v.11 no.1
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    • pp.27-33
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    • 2009
  • A study of fracture to material is getting interest in nuclear and aerospace industry as a viewpoint of safety. Acoustic emission (AE) is a non-destructive testing and new technology to evaluate safety on structures. In previous research continuously, all tensile tests on the pre-defected coupons were performed using the universal testing machine, which machine crosshead was move at a constant speed of 5mm/min. This study is to evaluate an AE source characterization of SM45C steel by using k-nearest neighbor classifier, k-NNC. For this, we used K-means clustering as an unsupervised learning method for obtained multi -variate AE main data sets, and we applied k-NNC as a supervised learning pattern recognition algorithm for obtained multi-variate AE working data sets. As a result, the criteria of Wilk's $\lambda$, D&B(Rij) & Tou are discussed.

Evaluation of energy release rate of composites laminated with finite element method

  • Achache, Habib;Boutabout, Benali;Benzerdjeb, Abdelouahab;Ouinas, Djamel
    • Structural Engineering and Mechanics
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    • v.55 no.1
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    • pp.191-204
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    • 2015
  • Control of the mechanical behavior of composite materials and structures under monotonic and dynamic loads for cracks and damage is a vast and complex area of research. The modeling of the different physical phenomena and behavior characteristics of a composite material during deformation play an important role in the structural design. Our study aims to analyze numerically the energy release rate parameter G of a composite laminated plate (glass or boron / epoxy) cross-ply [$+{\alpha}$, $-{\alpha}$] in the presence of a crack between two circular notches under the effect of several parameters such as fiber orientation ${\alpha}$, the crack orientation ${\beta}$, the orientation ${\gamma}$ of the two considered circular notches and the effect of mechanical properties. Our results show clearly that both notches orientation has more effect on G than the cracks and fibers orientations.

Shaping Analysis to decide the Design Condition of a Passive-type Radar Reflector (수동형 레이더 리프렉터의 설계조건 결정을 위한 형상분석)

  • Yim, Wung-Bin;Kim, Woo-Suk
    • Journal of Navigation and Port Research
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    • v.26 no.2
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    • pp.199-207
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    • 2002
  • Radar Cross Sections(RCS) for the radar targets are measured and their performance characteristics are analyzed through computer simulation. In addition, constructional features for the commercial radar reflectors are investigated. Then, the optimum design condition of a passive-type radar reflector was chosen. The results show that the octahedral-type radar reflector with 10$\lambda$ sized circular plates has best performance in X-band($\lambda$=3.2cm). However, to comply with newly adopted 2000 SOLAS regulations, larger sized circular plate is required to provide at both X-band and S-band.

High Dose Rate Ir-192 Source Calibration Method with Newly Designed Calibration Jig (고선량 Ir-192선원 교정기의 제작 및 특성)

  • Yi, Byong-Yong;Choi, Eun-Kyung;Chang, Hye-Sook
    • Radiation Oncology Journal
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    • v.7 no.2
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    • pp.299-303
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    • 1989
  • Authors have developed highly reproducible calibration method for the Micro-Selectron HDR Ir-192 system (Nucletron, Motherland). The new jig has a 10cm radius circular hole in the $30cm{\times}30cm{\times}0.2cm$ acrylic plate, and 5F flexible bronchial tubes are attached around the hole. The source moves along the circle in the tubes and the ionization chamber is placed verticaly at the center of the circular hole (center of the jig). Dose distribution near the center was derived theoretically, and measured with the film dosimetry system. Theoretical calculation and measurement show the error margin below $0.1\%$ for 1mm or 2mm position deviation. We have measured at 12 and 24 points of circle with 1, 6, 11 and 21 second dwell time of source in order to calculate the activity of the source. Measurements have been repeated daily for 50 days. The accuracy and the reproducibility are below $1\%$ error margin. The half life of the source from our measurement is estimated $73.4\pm0.4$ days.

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Prediction of Total Acoustic Radiation Power of the Submerged Circular Cylindrical Structures (수중 원통형 구조물의 총 음향방사파워 예측)

  • Han, Seungjin;Lee, Jongju;Kang, Myunghwan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.11
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    • pp.876-882
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    • 2014
  • This study investigates an efficient method to estimate the total acoustic radiation power of submerged circular cylindrical structures. Since the acoustic radiation power of submerged vehicles can be changed during the operation, the estimation for its monitoring onboard is required to accomplish the missions. The total acoustic radiation power is estimated using the measured velocity and the calculated radiation efficiency of the surface which consists of submerged rectangular plate elements. Experiments are carried out to validate the estimation approach. Comparisons of the estimation results with the measurements show that they are in a good agreement for the mid-high frequency range and match well for the cases of different excitation locations which correspond to the different operation modes of underwater vehicles as well. Therefore, this estimation method can be applied effectively to the development of the radiated noise monitoring-system.

A Study on the Load Characteristics of a Swash Plate Piston Pump Holder (Cradle) with Grooves Considering the Squeeze Effect (스퀴즈 효과를 고려한 사판식 피스톤 펌프 홀더의 그루브 유무에 따른 부하특성에 대한 연구)

  • Ju, Gyeong Jin;Seol, Sang Suk;Kim, Yong Gil;Kim, Soo Tae
    • Journal of Drive and Control
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    • v.17 no.1
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    • pp.21-26
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    • 2020
  • The load characteristics of a piston pump holder due to the squeeze effect are influenced by the surface shape and gap thickness of the holder (cradle). Therefore, the pressure distribution and the load capacity of the piston pump holder due to the squeeze effect are studied by using the CFD software and the surface shape and gap thickness of the piston pump holder are considered. In order to verify the accuracy of numerical results, the load capacities of a circular plate holder are numerically studied, and the accuracy of numerical results is verified by comparing with the theoretical results. Also, the pressure distribution and load capacity of the rectangular plate holder of a piston pump are obtained by using the CFD software. The results show that the load capacity of the square plate holder with grooves is slightly higher at a low gap thickness, but the effects of the number and arrangement of grooves on the load capacity of the holder are weak. We conclude that the load capacity and the maximum pressure are slightly affected due to the existence of grooves on the holder surface, and the fluid storing effect of the holder surface grooves during the operation is likely to prevent the dry-sticking phenomenon.

Effect of Periodic Passing Wake on the Flow Field of a Film-Cooled Flat Plate(I) (주기적인 통과후류가 막냉각되는 평판의 유동장에 미치는 영향(1);압력면과 흡입면에 대한 영향(1))

  • Kuk, Keon;Lee, Joon-Sik;Kauh, Sang-Ken
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.6
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    • pp.1931-1940
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    • 1996
  • The effect of periodic passing wake on the film-coolant flow issuing normally from a flat plate was investigated experimentally. The passing wake was generated by rotating thin circular bars. Depending on the rotational direction the test plate could be simulated as a pressure surface or a suction surface of a gas turbine blade. The phase-averaged velocity components were measured using an X-type hot-wire probe. The Reynolds number based on the free-stream velocity and injection hole diameter was 23, 500 and the velocity ratio which is the ratio of film coolant velocity to free-stream velocity was 0.5. The velocity-triangle induced by the wake was similar to that induced by the one generated at the blade trailing edge. The vertical velocity component induced by the passing wake, which approaches to the suction surface and moves away from the pressure surface, played a dominant role in the variation of the flow field. The variation in the phase-averaged velocity on the pressure surface was greater than on the suction surface, but the turbulence kinetic energy variation on the suction surface appeared larger than on the pressure surface.

Numerical Fatigue Life Prediction of IGBT Module for Electronic Locomotive (수치해석을 이용한 전동차용 IGBT 모듈의 피로 수명 예측)

  • Kwon, Oh Young;Jang, Young Moon;Lee, Young-ho;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.1
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    • pp.103-111
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    • 2017
  • In this study, the thermomechanical stress and fatigue analysis of a high voltage and high current (3,300 V/1200 A) insulated gate bipolar transistor (IGBT) module used for electric locomotive applications were performed under thermal cycling condition. Especially, the reliability of the copper wire and the ribbon wire were compared with that of the conventional aluminum wire. The copper wire showed three times higher stress than the aluminum wire. The ribbon type wire showed a higher stress than the circular type wire, and the copper ribbon wire showed the highest stress. The fatigue analysis results of the chip solder connecting the chip and the direct bond copper (DBC) indicated that the crack of the solder mainly occurred at the outer edge of the solder. In case of the circular wire, cracking of the solder occurred at 35,000 thermal cycles, and the crack area in the copper wire was larger than that of the aluminum wire. On the other hand, when the ribbon wire was used, the crack area was smaller than that of the circular wire. In case of the solder existing between DBC and base plate, the crack growth rate was similar regardless of the material and shape of the wire. However, cracking occurred earlier than chip solder, and more than half of the solder was failed at 40,000 cycles. Therefore, it is expected that the reliability of the solder between DBC and base plate would be worse than the chip solder.

Centrifugal Model Test on Behavior of Underground Corrugated Steel Plate with Compaction Degree (다짐도에 따른 지중파형강판의 거동에 대한 원심모형실험)

  • Heo, Yol;Kwon, Seonuk;Kim, Hongjong;Bae, Wooseok
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.83-90
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    • 2011
  • A series of centrifugal model test was conducted to investigate the distribution of vertical earth pressure on circular ductile underground corrugated steel plate waterway culvert with considering the compaction degree of the backfill in the high landfilled embankment section. The compaction degree of backfill was varied to 80, 85, 90, and 95% at the 53g-level gravity considering the similarity of the site. As a result of this test, the load reduction factor by the arching effect of the top of corrugated steel plate showing ductile behavior nearly agreed with the load reduction factor according to the compaction degree of backfill specified in the AISI(2002) design method. The vertical earth pressure measured at the top of the corrugated steel plate was linearly decreased as the compaction degree increased. The greater the compaction degree of backfill was, the greater the reduction of surface loading on the top of the corrugated steel plate by arching effect. The load decreased by arching effect on top of the corrugated steel plate was transferred to the side backfill of the corrugated steel plate(EP 1) and the outside of backfill(EP 3).