• Title/Summary/Keyword: joint thickness

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Bending Strain Effect on the Critical Current of Jointed BSCCO Tapes

  • Shin, Hyung-Seop;Dedicatoria, Marlon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.217-217
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    • 2009
  • In this study, the effect of bending strain on the transport property and critical current of lap and butt-jointed BSCCO tapes have been investigated. The samples were joined using a mechanically controlled jointing procedure. In order to ensure a uniform pressure application at the joint part, a single point contact has been devised and also to achieve a uniform thickness at the joint interface.

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Joint Characteristics in Layered Rocks (층상 암석에서 절리의 특성 연구)

  • Chang, Tae-Woo
    • The Journal of Engineering Geology
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    • v.19 no.2
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    • pp.145-152
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    • 2009
  • Joints are planar tensile opening-mode fractures whose relative motion, as the fracture propagates, is perpendicular to bedding plane and occur in a systematic manner to form a joint set. This paper discusses the mechanical control of joint propagation, the relationship between join spacing and layer thickness, the join saturation, the frequency distribution of join spacing, the joint density, the cross joint, and the development mechanism of joint from a lot of recent joint studies in sedimentary rocks.

Investigation of the tensile behavior of joint filling under experimental test and numerical simulation

  • Fu, Jinwei;Haeri, Hadi;Sarfarazi, Vahab;Marji, Mohammad Fatehi;Guo, Mengdi
    • Structural Engineering and Mechanics
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    • v.81 no.2
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    • pp.243-258
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    • 2022
  • In this paper, tensile behavior of joint filling has been investigated under experimental test and numerical simulation (particle flow code). Two concrete slabs containing semi cylinder hole were prepared. These slabs were attached to each other by glue and one cubic specimen with dimension of 19 cm×15 cm×6 cm was prepared. This sample placed in the universal testing machine where the direct tensile stress can be applied to this specimen by implementing a special type of load transferring device which converts the applied compressive load to that of the tensile during the test. In the present work, two different joint filling thickness i.e., 3 mm and 6 mm were prepared and tested in the laboratory to measure their direct tensile strengths. Concurrent with experimental test, numerical simulation was performed to investigate the effect of hole diameter, length of edge notch, filling thickness and filling length on the tensile behavior of joint filling. Model dimension was 19 cm×15 cm. hole diameter was change in four different values of 2.5 cm, 5 cm, 7.5 cm and 10 cm. glue lengths were different based on the hole diameter, i.e., 12.5 cm for hole diameter of 2.5 cm, 10 cm for hole diameter of 5 cm, 7.5 cm for hole diameter of 7.5 cm and 5 cm for hole diameter of 10 cm. length of edge notch were changed in three different value i.e., 10%, 30% and 50% of glue length. Filling thickness were changed in three different value of 3 mm, 6 mm and 9 mm. Tensile strengths of glue and concrete were 2.37 MPa and 6.4 MPa, respectively. The load was applied at a constant rate of 1 kg/s. Results shows that hole diameter, length of edge notch, filling thickness and filling length have important effect on the tensile behavior of joint filling. In fixed glue thinks and fixed joint length, the tensile strength was decreased by increasing the hole diameter. Comparing the results showed that the strength, failure mechanism and fracture patterns obtained numerically and experimentally were similar for both cases.

Effects of the Electroless Ni-P Thickness and Assembly Process on Solder Ball Joint Reliability (무전해 Ni-P 두께와 Assembly Process가 Solder Ball Joint의 신뢰성에 미치는 영향)

  • Lee, Ji-Hye;Huh, Seok-Hwan;Jung, Gi-Ho;Ham, Suk-Jin
    • Journal of Welding and Joining
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    • v.32 no.3
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    • pp.60-67
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    • 2014
  • The ability of electronic packages and assemblies to resist solder joint failure is becoming a growing concern. This paper reports on a study of high speed shear energy of Sn-4.0wt%Ag-0.5wt%Cu (SAC405) solder with different electroless Ni-P thickness, with $HNO_3$ vapor's status, and with various pre-conditions. A high speed shear testing of solder joints was conducted to find a relationship between the thickness of Ni-P deposit and the brittle fracture in electroless Ni-P deposit/SAC405 solder interconnection. A focused ion beam (FIB) was used to polish the cross sections to reveal details of the microstructure of the fractured pad surface with and without $HNO_3$ vapor treatment. A scanning electron microscopy (SEM) and an energy dispersive x-ray analysis (EDS) confirmed that there were three intermetallic compound (IMC) layers at the SAC405 solder joint interface: $(Ni,Cu)_3Sn_4$ layer, $(Ni,Cu)_2SnP$ layer, and $(Ni,Sn)_3P$ layer. The high speed shear energy of SAC405 solder joint with $3{\mu}m$ Ni-P deposit was found to be lower in pre-condition level#2, compared to that of $6{\mu}m$ Ni-P deposit. Results of focused ion beam and energy dispersive x-ray analysis of the fractured pad surfaces support the suggestion that the brittle fracture of $3{\mu}m$ Ni-P deposit is the result of Ni corrosion in the pre-condition level#2 and the $HNO_3$ vapor treatment.

Effect of Tool Plunge Depth on Weldability of Dissimilar Al5083-O/DP590 Friction Spot Joint (이종재 Al5083-O/DP590 마찰교반점용접시 툴의 삽입깊이(Plunge Depth)가 용접성에 미치는 영향)

  • Jeong, Su-Ok;Bang, Han-Sur;Bang, Hee-Seon
    • Journal of Welding and Joining
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    • v.34 no.3
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    • pp.17-22
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    • 2016
  • In terms of mechanical and metallurgical characteristics, the effect of tool plunge depths(0.2, 0.5, 0.7, 1.0, 1.5mm) on weldability in dissimilar Al5083-O/DP590 friction spot joint has been clarified. From the results, it is found that the stirred nugget was stably formed at a plunge depth of more than 0.7mm, which is caused by improved stirring action against each other material. With increasing a plunge depth, the thickness of intermetallic compound(IMC) layer in Al5083-O/DP590 joint has a tendency to increase. The tensile shear strength reaches to the maximum failure load of 6.5kN at a plunge depth of 0.7mm due to relatively small decrease in the thickness of Al5083-O sheet and relatively minute thickness of IMC layer, compared with those of other plunge depth conditions.

Scoring System for Factors Affecting Aggravation of Lumbar Disc Herniation

  • Lee, Sung Wook;Kim, Sang Yoon;Lee, Jee Young
    • Investigative Magnetic Resonance Imaging
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    • v.22 no.1
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    • pp.18-25
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    • 2018
  • Purpose: To investigate the various imaging factors associated with aggravation of lumbar disc herniation (LDH) and develop a scoring system for prediction of LDH aggravation. Materials and Methods: From 2015 to 2017, we retrospectively reviewed the magnetic resonance imaging (MRI) findings of 60 patients (30 patients with aggravated LDH and 30 patients without any altered LDH). Imaging factors for MRI evaluation included the level of LDH, disc degeneration, back muscle atrophy, facet joint degeneration, ligamentum flavum thickness and interspinous ligament degeneration. Flexion-extension difference was measured with simple radiography. The scoring system was analyzed using receiver operating characteristic (ROC) analysis. Results: The aggravated group manifested a higher grade of disc degeneration, back muscle atrophy and facet degeneration than the control group. The ligamentum flavum thickness in the aggravated group was thicker than in the group with unaltered LDH. The summation score was defined as the sum of the grade of disc degeneration, back muscle atrophy and facet joint degeneration. The area under the ROC curve showing the threshold value of the summation score for prediction of aggravation of LDH was 0.832 and the threshold value corresponded to 6.5. Conclusion: Disc degeneration, facet degeneration, back muscle atrophy and ligamentum flavum thickness are important factors in predicting aggravation of LDH and may facilitate the determination of treatment strategy in patients with LDH. The summation score is available as supplemental data.

Analysis of Angular Deformation in Multi-pass Butt Joint Welding of Thick Plates with X-shape Grooves using the Finite Element Method (X형 개선을 가진 후판 맞대기 용접에 있어서 유한요소법을 이용한 각변형 해석)

  • Yang, Young-Soo;Bae, Kang-Yul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.4
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    • pp.169-176
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    • 2018
  • Removal of angular deformation induced during the welding of butt joints in thick steel plates needs expert skill and is costly. To reduce deformation, proper joint designs are studied with a prediction of deformation prior to welding. However, as the thickness of a plate increases, a predictive analysis of the welding process is more difficult, especially if there is an increase in the number of welding passes in the joint. In this study, a numerical model with the finite element method (FEM) was developed to analyze the angular deformation in the multi-pass welding of butt joints of plates made of AH32 steel that had a thickness of up to 100 mm. A series of numerical simulations were then performed based on the developed model to predict the deformations for thick plates. With the results obtained by the analyses, this study suggested optimal X-shape grooves for the butt joints of thick plates to minimize the angular deformation. As the thickness of the plate increased to 100 mm, the ratio of the depth of the front-side groove to that of the back-side groove should be gradually increased to nearly 1:3.

A Study of Structural Strength Characteristics for Application of Carbon Composites in Fishing Vessel Hull (어선 선체의 탄소섬유복합재 적용을 위한 구조 강도 특성 연구)

  • Hae-Soo Lee;Hyung-Won Lee;Seung-June Choi;Myung-Jun Oh
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.46 no.3
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    • pp.69-77
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    • 2023
  • Recently, carbon composites have been applied to various fields. However, carbon composites have not been applied to the fishing vessel field due to its structure standards centered on glass composites. In this study, a structural strength evaluation study was conducted for the application of carbon composites in the fishing vessel field. Hull minimum thickness verification test and hull joint verification test were conducted. Compared to glass composites, the verification was based on equivalent or better performance. The results show that carbon composites can reduce the weight by 20% compared to glass composites. For hull joints, it was necessary to increase the thickness of the joint seam by the thickness of the hull to apply carbon composite. Through this study, a standard for the application of carbon composites to fishing vessel can be established.

Experimental Study on Evaluation of Bonding Strength of Adhesively Bonded Joints by Adhesive (접착제 접합 이음부 접합강도 평가에 대한 실험적 연구)

  • Kang, Ki-Yeob;Lee, Jae-Myung
    • Journal of Welding and Joining
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    • v.30 no.6
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    • pp.62-67
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    • 2012
  • In this study, the bonding strengths of adhesively bonded joints are experimentally investigated. A series of lap-shear tests are conducted using single lap type adhesive joints. In order to analyse the joint fabrication factors that affected the bonding strength, the parametric tests are conducted with various thickness of adhesive, surface roughness and fillet of adhesive. In addition, for the comparative study with the welded joint, lap-shear tests using specimens with 2 welded sides and 4 welded sides are also carried out. The quantitative results of the strength analysis are summarized, and some proposals are made on setting up testing standards for adhesively bonded joints.

Study on NbTi superconducting joint process for high field MRI magnet (고자장 MRI 마그네트를 위한 NbTi 초전도 접합 공정 연구)

  • 하동우;오상수;하홍수;이남진;고락길;권영길;류강식
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.165-167
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    • 2002
  • NbTi/Cu superconducting wires were jointed inserting the NbTi filaments into Cu/NbTi sleeve and pressing it. When the NbTi filaments were inserted into Cu/NbTi sleeve, additional NbTi filaments were inserted together to increase the numbers of filaments in the hole of sleeve. Critical current of the joint of 28 filaments wires with 1.7 mm thickness of dimple was 450 A at 4.2K, 0.5T. Ic of the joint of 54 filaments wires with 2.0 mm thickness of dimple was 600 A at 4.2K, 2T. It is possible to manufacture MRI magnet by using these results.

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