• Title/Summary/Keyword: 접합면

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The Tensile Strength at Room Temperature of Brazing Section for Materials used for Liquid Rocket Engine Combustion Chamber (액체 로켓엔진 연소기 사용 재료의 상온 브레이징부 인장강도 특성)

  • 정용현;류철성;최민수
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.4
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    • pp.73-79
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    • 2003
  • The tensile strength test and the analysis for the section of brazing were performed in the cases of materials used for combustion chamber of regeneratively cooled liquid rocket engine. BNi-2 and BNi-7 based on nickel were used for brazing as filler metal. The properties of material and filler metal were analyzed by tensile strength test and metal microscope for 12 specimens. The tensile-strength of brazing for chrome-copper alloy and other kinds of alloy was higher than that of chrome-zirconium-copper alloy and other kinds of alloy The tensile strength in the case of BNi-2 as filler metal was higher than that of BNi-7 because the wetting property of BNi-2 was better than that of BNi-7.

Scarf Welding of Thin Substrates and Evaluation of the Tensile Properties (박형 기판의 사면 접합 공정 및 인장 특성 평가)

  • Beomseok Kang;Jeehoo Na;Myeong-Jun Ko;Minjeong Sohn;Yong-Ho Ko;Tae-Ik Lee
    • Journal of the Microelectronics and Packaging Society
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    • v.30 no.3
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    • pp.102-110
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    • 2023
  • This paper introduces scarf welding process of thin substrates using flexible laser transmission welding (f-LTW) technology. We examined the behavior of tensile strength relative to the scarf angle for flexible applications. Thin plastic substrates with the thickness of less than 100 ㎛ were bonded and a jig to form a slope at the edge of the substrate was developed. By developing the scarf welding process, we successfully created a flexible bonding technology that maintains joint's thickness after the process. The tensile strength of the joint was assessed through uniaxial test, and we found that the tensile strength increases as the slope of bonding interface decreases. By conducting stress analysis at the bonding interface with respect to the slope angle, design factor of bonding structure was investigated. These findings suggest that the tensile strength depends on the geometry of the joint, even under the same process conditions, and highlights the significance of considering the geometry of the joint in welding processes.

Finite Element Analysis of Bolted Connections Using Joint Elements (접합요소를 이용한 볼트 접합부의 유한요소해석)

  • 변대근;윤성기;박성수
    • Computational Structural Engineering
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    • v.7 no.2
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    • pp.139-146
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    • 1994
  • In this study, the finite element analysis using joint elements, bolt elements, and shell elements is presented to investigate the behavior of bolted connections. The contact of plates and the high-strength, pretensioned bolts are simply idealized by joint elements and bolt elements, respectively. The initial stiffness is determined through the presented method and the non-linear analysis is archived by a constant-arc-length method based on Newton-Raphson method. The analysis results of a semi-rigid connection(web & flange angles) and a moment connection (shear & moment plates) demonstrate the exactness and applicability of the presented method. And the results indicates that the consideration of slip and 3-dimensional deformation is needed for an accurate prediction of bolted connections.

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An Evaluation of Slip Coefficient in High Strength Bolt Joint using Zn/Al Metal Spray Corrosion Resistance Method (Zn/Al 금속용사 방식공법을 적용한 고력볼트 접합부의 미끄럼계수 평가)

  • Kim, Tae-Soo;Lee, Han-Seung;Tae, Sung-Ho;Ahn, Hyun-Jin;Oh, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.5
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    • pp.114-122
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    • 2007
  • In high strength bolted joints, the corrosion of base material causes the reduction of slip resistance of the joints. In this study, tensile tests on slip-critical joints utilizing Zn/Al metal spraying corrosion resistance method were carried out in order to prevent the corrosion and meet the required mechanical characteristics of joints. In addition, slip coefficient and surface roughness were calculated. The key parameters were surface finishing condition and thickness of coating with the identical geometry in all specimens. From the results, it is found that the slip coefficient of the joints with coated finish after sand blast treatment as well as those of non-coated joints with only sand blast treatment were similar or superior to 0.45, which is a specification criteria of slip coefficient in friction-typed joints.

The Seismic Performance of Non-Ductile Reinforced Concrete (RC) Frames with Engineered Cementitious Composite (ECC) Wing Panel Elements (ECC 날개벽 요소로 보강된 비내진상세를 갖는 철근콘크리트 골조의 내진성능)

  • Kang, Dae-Hyun;Ok, Il-Seok;Yun, Hyun-Do;Kim, Jae-Hwan;Yang, Il-Seung
    • Journal of the Korea Concrete Institute
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    • v.27 no.5
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    • pp.541-549
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    • 2015
  • This study was conducted to experimentally investigate the seismic retrofitting performance of non-ductile reinforced concrete (RC) frames by introducing engineered cementitious composite (ECC) wing panel elements. Non-ductile RC frame tested in this study were designed and detailed for gravity loads with insufficient or no consideration to lateral loads. Therefore, Non-ductile RC frame were not satisfied on present seismic code requirements. The precast ECC wing panels were used to improve the seismic structural performance of existing non-ductile RC frame. A series of experiments were carried out to evaluate the structural performance of ECC wing panel elements alone a non-ductile RC frame strengthened by adding ECC panel elements. Failure pattern, strength, stiffness and energy dissipation characteristics of specimens were evaluated based on the test results. The test results show that both lateral strength and stiffness were significantly improved in specimen strengthened than non-ductile RC frame. It is noted that ECC wing wall elements application on non-ductile RC frame can be effective alternative on seismic retrofit of non-ductile building.

The Effect of thin Stepped Oside Structure Along Contact Edge on the Breakdown Voltage of Al-nSi Schottky Diode (Al-nSi 쇼트키 다이오드의 접합면 주위의 얇은 계단형 산화막 구조가 항복 전압에 미치는 영향)

  • 장지근;김봉렬
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.3
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    • pp.33-39
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    • 1983
  • New Schottky devices with thin stepped oxide layer (about 1000 ${\AA}$) along the edge of metal-semiconductor junction have been designed and fabricated. The breakdown voltages of these diodes have been compared with those of conventional metal overlap and P guard ring Schottky diode structures. Thin stepped oxide layer has been grown by the process of T.C.E. oxidation. In order to compare and demonstrate the improved down phenomena of these devices, conventional metal overlap diode and P guard ring which have the same dimension with new devices have also been integrated in a same New Schottty devices structured with thin stepped oxide layer have shown significant improvement in breakdown phenomena compared with conventional diodes.

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Study on the pn Junction Device Using the POCl3 Precursor (POCl3를 사용한 pn접합 소자에 관한 연구)

  • Oh, Teresa
    • Journal of the Korean Vacuum Society
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    • v.19 no.5
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    • pp.391-396
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    • 2010
  • The pn junction for solar cell was prepared on p-type Si wafer by the furnace using the $POCl_3$ and oxygen mixed precursor to research the characteristic of interface at pn junction. The sheet resistance was decreased in accordance with the increasing the diffusion process time for n-type doping on p-type Si wafer. The electron affinity at the interface in the pn junction was decreased with increasing the amount of n-type doping and the sheet resistance also decreased. Consequently, the drift current due to the generation of EHP increased because of low potential barrier. The efficiency and fill factor were increased at the solar cell with increasing the diffusion process time.

Inelastic Analysis of Reinforced Concrete Structure Subjected to Cyclic Loads with Confining Effects of Lateral Tie (횡방향 철근의 구속효과를 고려한 반복하중을 받는 철근콘크리트 부재의 비탄성해석)

  • 유영화;최정호;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.1
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    • pp.79-93
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    • 1998
  • The eigenvalue problem is presented for the building with added viscoelastic dampers by using component mode method. The Lagrange multiplier formulation is used to derive the eigenvalue problem which is expressed with the natural frequencies of the building, the mode components at which the dampers are added, and the viscoelastic property of the damper. The derived eigenvalue problem has a nonstandard form for determining the eigenvalues. Therefore, the problem is examined by the graphical depiction to give new insight into the eigenvalues for the building with added viscoelastic dampers. Using the present approach the exact eigenvalues can be found and also upper and lower bounds of the eigenvalues can be obtained.

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Thermal stress Intensity Factors for the Interfacial Crack on a Cusp-Type Inclusion (커스프형 강체함유물 상의 접합경계면 균열에 대한 열응력세기계수)

  • 이강용;장용훈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.7
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    • pp.1255-1265
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    • 1992
  • Under uniform heat flow, the thermal stress intensity factors for the interfacial crack on a rigid cusp-type inclusion are determined by Hilbert problem expressed with complex variable. The thermal stress intensity factors are expressed in terms of the periodic function of heat flow angle. When the tip of the interfacial crack meets that of the cusp crack, the thermal stress intensity factors have singularities. The thermal stress intensity factors at the interfacial crack tip located in the distance from the cusp crack tip vary with the location of the interfacial crack tip. From the results of the analysis, the complex potential functions and the thermal stress intensity factors for the cusp-type inclusion without the interfacial crack are derived under the cusp surface boundary conditions insulated or fixed to zero relative temperature.