• Title/Summary/Keyword: 판재

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Effects of Rubber Loading on the Ultrasonic Backward Radiation Profile of Leaky Lamb Wave (고무 접합이 후방복사된 리키 램파 프로파일에 미치는 영향)

  • Song, Sung-Jin;Kwon, Sung-Duk;Jung, Min-Ho;Kim, Young-H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.5
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    • pp.508-515
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    • 2002
  • The characterization of adhesive property in multi-layer materials has been hot issue for a long time. In order to evaluate adhesive properties, we constructed fully automated system for the backward radiation of leaky Lamb wave. The backward radiation profiles were obtained for the bare steel plate and plates with rubber-loading. The rf waveforms and frequency spectra of backward radiation show the characteristics of involved leaky Lamb wave modes. As the thickness of rubber-loading increased, the amplitude of profile at the incident angle of $13.4^{\circ}$ exponentially decreased. Scanning the incident position over the partially rubber-loaded specimen shows good agreement with the actual rubber-loading. The backward radiation of leaky Lamb wave has great potential to evaluate the adhesive condition as well as material properties of plates.

The Estimated Drying Schedules of Larix leptolepis and Pinus koraiensis (낙엽송과 잣나무재의 추정건조(推定乾燥)스케쥴)

  • Park, Jong-Su;Kim, Su-Chang
    • Journal of Forest and Environmental Science
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    • v.11 no.1
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    • pp.50-60
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    • 1995
  • This study was carried out to estimate drying schedules of Larix Leptolepis and Pinus koraiensis by oven-drying at $100^{\circ}C$ which aimed to elucidate the characteristics such as current moisture content, drying process. initial check, collapse, internal check and drying rate during drying following each board thickness (2, 3. 4, 5, 6cm). the results were summerized as follows; Current moisture content of each board showed a rapid drying curve with the decrease of board thickness. At 20% moisture content, the drying rate of Larix leptolepis was higher than that of Pinus koraiensis and the drying rate of boards was lower with the increase of board thickness. From the estimated drying schedules. the initial conditions of drying of Larix leptolepis had to be milder than those of Pinus koraiensis and the boards thickness of 5cm, 6cm had to be most mild conditions.

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Test and Numerical Analysis for Penetration Residual Velocity of Bullet Considering Failure Strain Uncertainty of Composite Plates (복합판재의 파단 변형률 불확실성을 고려한 탄 관통 잔류속도에 대한 시험 및 수치해석)

  • Cha, Myungseok;Lee, Minhyung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.3
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    • pp.281-288
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    • 2016
  • The ballistic performance data of composite materials is distributed due to material inhomogeneity. In this paper, the uncertainty in residual velocity is obtained experimentally, and a method of predicting it is established numerically for the high-speed impact of a bullet into laminated composites. First, the failure strain distribution was obtained by conducting a tensile test using 10 specimens. Next, a ballistic impact test was carried out for the impact of a fragment-simulating projectile (FSP) bullet with 4ply ([0/90]s) and 8ply ([0/90/0/90]s) glass fiber reinforced plastic (GFRP) plates. Eighteen shots were made at the same impact velocity and the residual velocities were obtained. Finally, simulations were conducted to predict the residual velocities by using the failure strain distributions that were obtained from the tensile test. For this simulation, two impact velocities were chosen at 411.7m/s (4ply) and 592.5m/s (8ply). The simulation results show that the predicted residual velocities are in close agreement with test results. Additionally, the modeling of a composite plate with layered solid elements requires less calculation time than modeling with solid elements.

Shape Analysis for the Activation of a Traditional Zzaim (전통짜임의 활성화를 위한 조형적 분석)

  • Namgoong, Sun
    • The Journal of the Korea Contents Association
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    • v.13 no.4
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    • pp.418-426
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    • 2013
  • This study aims to analyze the formativeness of zzaim (traditional craft techniques to combine two or more materials to make an angle or to weave them to make a slope side) and systematically classified these techniques to help furniture manufacturers effectively utilize them in the design of contemporary furniture. From this data, furniture manufacturers can have benefits to understand which type of zzaim techniques will be appropriate to their plan of building furniture, and practically use relevant techniques in the field. This study classified four different applications of zzaim techniques depending on sites, such as (1) the top, (2) middle body, (3) lower body, and (4) legs of furniture. In summary, zzaim techniques are differently applied depending on the application sites and formative types of furniture. This feature makes general furniture manufacturers who want to apply zzaim techniques for the first time have hard time to understand which kind of technique should be applied to which part. Recognizing this problem, this study expects general manufacturers as well as master artisans to more effectively utilize zzaim techniques by providing the systematic data on the formative analysis of types of furniture and application sites.

Theoretical Models for Predicting Racking Resistance of Shear Walls (전단벽의 전단성능 예측 모형)

  • Jang, Sang Sik
    • Journal of the Korean Wood Science and Technology
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    • v.30 no.4
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    • pp.96-105
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    • 2002
  • Shear wall is the most important component resisting lateral loads imposed to a building by wind or earthquake. In shear walls, lateral load applied to framing is transmitted to sheathing panel through nailed joints between sheathing and framing so that the load is resisted by in-plane shear strength of sheathing. Therefore, nailed joints are the most basic and important component in the viewpoint of stiffness and strength of shear walls. In this study, stiffness and strength of single nailed joint were measured by single shear tests of nailed joints and used as input for theoretical models developed to estimate racking behavior of shear walls. And shear walls were tested to check the accuracy of theoretical models estimating racking resistance of shear walls. Stiffness of nailed joint was affected by grain direction of stud but direction of sheathing panel had little effect. Behavior of nailed joint and shear walls under lateral loads could be represented by three lines. Theoretical model II was more accurate than theoretical model I in estimating racking behavior of shear wall under loads.

Explosion Modelling for Crack Propagation near Blast holes in Rock Plate (암석판재에서 발파공 부근 균열전파에 대한 폭원모델링)

  • Choi, Byung-Hee;Kang, Myoung-Soo;Ryu, Chang-Ha;Kim, Jae-Woong
    • Explosives and Blasting
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    • v.33 no.1
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    • pp.13-20
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    • 2015
  • Recently, as the demand for development and utilization of underground space is increasing worldwide, the blast damaged zone has become a major issue in constructing underground structures. In this study, numerical analyses were performed for modelling a small-scale blasting of rock plates using PFC3D and ANSYS LS-DYNA. In order to verify the analysis results, several test blasts were conducted. It is concluded from the study that the numerical modelling methods well simulate the crack propagation procedure near blast holes under given conditions.

Spring-back Evaluation of Automotive Sheets Based on Combined Isotropic-Kinematic Hardening Rule (혼합 등방-이동 경화규칙에 기초한 자동차용 알루미늄합금 및 Dual-Phase 강 판재의 스프링백 예측)

  • ;;;Chongmin kim;Michael L. Wenner
    • Transactions of Materials Processing
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    • v.13 no.1
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    • pp.15-20
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    • 2004
  • In order to evaluate spring-back behavior in automotive sheet forming processes, a panel shape idealized as a double S-rail has been investigated. After spring-back has been predicted for double S-rails using the finite element analysis, results has been compared with experimental measurements for three automotive sheets. To account for hardening behavior such as the Bauschinger and transient effects in addition to anisotropic behavior, the combined isotropic-kinematic hardening law based on the Chaboche type model and a recently developed non-quadratic anisotropic yield function have been utilized, respectively.

The Effect of Probe Tool Speed on Weld Characteristics and Strength during Friction Stir Spot Welding of Mg-alloy Sheets (마그네슘 합금 판재의 마찰 교반 점용접 시 툴 속도가 접합특성 및 강도에 미치는 영향)

  • Jung, Yoon-Chul;Park, Sung-Su;Shin, Hyung-Seop;Choi, Kwang
    • Proceedings of the KWS Conference
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    • 2010.05a
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    • pp.64-64
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    • 2010
  • 최근 그린 친환경, 지구온난화방지와 환경 부하물질저감, 기기 고효율화, 연비향상 등의 관점에서 항공기, 자동차 등 운송기계와 휴대용 전자제품 등 경량화가 요구되는 분야에서 경량합금의 사용이 급증하고 있다. 특히, 경량합금 중 가장 가벼운 마그네슘 합금은 최근 주목을 받고 있는 금속재료이다. 그러나 마그네슘합금은 알루미늄합금과는 달리 상온 성형성 및 접합성이 양호하지 않은 관계로 판재를 이용한 구조부품의 제작을 위해서는 많은 연구가 필요하다. 이러한 관점에서 본 연구는 마그네슘합금 판재의 마찰 교반 점용접을 시도하였다. CNC 밀링머신을 사용하여 프로브의 회전 및 삽입 속도에 변화를 주어 접합 특성을 평가하였고, 각 변수의 영향을 조사하였다. 적외선 열화상기와 로드셀을 사용하여 마찰 교반 점용접 중에 발생하는 교반부 온도와 접합부에 가해지는 수직부가하중의 거동을 측정하였다. 마찰 교반 점용접 후, 시험편의 접합 상태와 접합부 단면 관찰을 통해 접합 상태를 조사하였다. 그리고 인장전단 실험을 실시하여 마찰 교반 점용접된 시혐편의 접합강도를 평가하였고, 파단된 시험편의 파면을 관찰하였다.

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A Development of Object Shape Recognition Module using Laser Sensor (레이저 센서를 이용한 물체의 형상인식 모듈 개발)

  • Kwak, Sung-Hwan;Lee, Seung-Kyu;Lee, Seung-Jae;Kim, Young-Sik;Choi, Joong-Koung;Park, Mu-Hun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.215-221
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    • 2008
  • 무인 운반설비의 자동화 시스템 개발의 한 부분으로써 여러 Vision 센서 중 레이저 센서를 이용하여 작업공간상에 있는 판재류와 코일류의 경계부분을 인식한다. 다음으로 인식한 물체의 경계를 이용하여 3차원 공간상의 위치좌표를 추출하여 무인크레인에 이동해야할 위치좌표를 전달한다. 본 연구에서는, 첫 번째 레이저 센서를 이용한 물체의 경계 추출, 두 번째 레이저 센서의 z축 기울기 각 추출, 세 번째 인식한 경계를 이용하여 물체의 2차원 위치좌표 추출, 네 번째 레이저 센서를 이용하여 판재와 코일의 판별, 다섯 번째 물체 판별의 결과에 따른 판재와 코일의 3차원 위치좌표 추출을 목적으로 한다. 본 연구의 결과는 무인 운반설비의 자동화 시스템 개발에 상당한 도움이 될 것으로 기대된다.

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A Study on The Change of Insert Clamping Force Influence According to the Surface Treatment of Armor Aluminum Alloy Plate (장갑판재의 표면처리에 따른 인서트 체결력 변화 연구)

  • Hwang, Bu Il;Yang, Sang Hun;Kim, Chi Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.8
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    • pp.787-791
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    • 2015
  • In some cases which are unable to replace the inserts when the depot maintenance or performance improvement of armored vehicles are carried out could have a risk of declining clamping forces by re-processing chromate. The change in the clamping forces of inserts has been investigated by applying a chromate process to hold the insert on the aluminum plate of the armored vehicle in this paper. In order to identify the effect of types and surface treatment, the breaking strength has been measured by the equivalent test item to the actual conditions. These tests would contribute the establishment of the armored vehicle production process.