• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.10a
• /
• pp.185-188
• /
• 2004

Regarding some of the components of the Korean Tilting Train eXpress(TTX), the lightweight-vehicle development was mainly focused to this study, and so as using the materials, the existing material, steel or aluminum carbody was changed to the composite carbody with both design and manufacturing methods. Therefore the evaluation of the performance of joint strength between composite and metallic boundary area, especially the under frame and the carbody was required, and the compressive and the bending tests were conducted as the sub-scale specimen. In this evaluation, there was involved the sufficient strengths at the joint area between the underframe and the carbody, and is resulted as the increment of the safety factor through the observation of failure conditions.

• Journal of Welding and Joining
• /
• v.12 no.3
• /
• pp.48-55
• /
• 1994

In this experiment, to find optimum brazing conditions for Cu/Stainless Steel brazing using filler metals of Ag-Cu-Zn-Cd system, first of all spreading ratio was tested on 304 stainless Steel and low carbon steel. And then shear test of brazed joint was executed. As the result of that, the shear strengths of brazed joints were the range of 60-90 MPa. Through microstructure analysis for brazed interface layer, We found as follows. Firstly interface layer increased as time increased. Secondly continuous layer of Ag-Cd compound was observed along the side of stainless steel. Also by means of EDS analysis for fracture surface, ductile fracture was occurred and precipitates on the fracture surface were found to include Cr, Mn, Si in Ag-rich phase.

• Journal of Powder Materials
• /
• v.4 no.3
• /
• pp.196-204
• /
• 1997

Joining of AIN ceramics to W and Cu by active-metal brazing method was tried with use of (Ag-Cu)-Ti alloy as insert-metal. Joints were produced under various conditions of temperature, holding time and Ti-content in (Ag-Cu) alloy Reaction and microstructural development in bonded interface were investigated through observation and analysis by SEM/EDS, EPMA and XRD. Joint strengths were measured by shear test. Bonded interface consists of two layers: an insert-metal layer of eutectic Ag- and Cu-rich phases and a reaction layer of TiN. Thickness of reaction layer increases with bonding temperature, holding time and Ti-content of insert-metal. It was confirmed that the growth of reaction layer is a diffusion-controlled process. Activation energy for this process was 260 KJ/mol which is lower than that for N diffusion in TiN. Maximum shear strength of 108 MPa and 72 MPa were obtained for AIN/W and AIN/Cu joints, respectively. Relationship between processing variables, joint strength and thickness of reaction layer was also explained.

• ETRI Journal
• /
• v.37 no.5
• /
• pp.906-916
• /
• 2015

High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

• Structural Engineering and Mechanics
• /
• v.81 no.2
• /
• pp.243-258
• /
• 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.

• Korean Journal of Construction Engineering and Management
• /
• v.3 no.3 s.11
• /
• pp.103-111
• /
• 2002

A joint venture approach to the marketing, organization, and execution of a project should be considered when the combined strengths of two or more entities result in a joint organization with unique credentials in a targeted business area. A joint venture is based on a complementary relationship: one party may lack one or more major elements needed for market penetration, such as technology, design-construct capabilities, geographic location, or financial strength; the other party should be able to compensate for these areas of weakness. The purpose of this study is that suggests the development direction of a joint venture, the proper organizational approach

• Journal of Korean Society of Steel Construction
• /
• v.22 no.5
• /
• pp.435-443
• /
• 2010

The current design practice of an electric transmission tower is based on the allowable stress design. Design strengths of the electric transmission tower's compression member are determined by buckling the strength of the member itself without considering joint strength. There is a possibility of a joint failure prior to the buckling of a member. Therefore, in this study, joint strength is calculated for various member forces, and the shape of joint and database of strength were established. These data was compared with the member strength obtained from previous research studies based on an equivalent nonlinear analysis technique. Finally, practical evaluation and design method to distinguish failure mode in an electric transmission tower member is proposed.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.8
• /
• pp.613-618
• /
• 2013

In this paper a new concept on z-pinning technology named by authors as 'z-pinning patch' will be introduced, which advantage is easy application at manufacturing site of composite structures. Using the trial manufactured z-pinning patch, the z-pinned composite single-lap shear joint specimens were successfully manufactured and tested to check the improvement of joint strengths. The z-pin's material is stainless steel and its surface was machined as zagged shape and chemically corroded to improve joint force with composite materials.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.2
• /
• pp.520-528
• /
• 1996

Four point bending tests of the brazed joint composed of sintered silicon nitride and 0.2% carbon steel with Cusil ABA filler which were fabricated at 86$0^{\circ}C$ were performed at temperatures, 25, 100, 200, 300, 400, 50$0^{\circ}C$ From the experiments, the maximum bending strength was measured at 30$0^{\circ}C$ From the 3D FE analysis of the residual stress of the brazed joint, it was revealed that the thermally induced residual stresses were minimized when the environmental temperature was 35$0^{\circ}C$ Considering the degradation of the filler material at high temperatures, it was calculated that the maximum bending strength of the brazed joint occured just below the temperature of the minimum thermal residual stress and the thermal residual stress was the dominative parameter of the brazed joint.

• Advances in materials Research
• /
• v.1 no.3
• /
• pp.183-190
• /
• 2012

Brazing Mo using Ti and Ti-15-3 foils has been investigated in the experiment. For traditional furnace brazing, solidification shrinkage voids cannot be completely removed from the joint even the brazing temperature increased to 2013 K and 160 ${\mu}m$ thick Ti foil applied in brazing. Similar results are observed from the joint using Ti-15-3 filler. In contrast, the quality of laser brazed joint is much better than that of furnace brazed joint. A sound joint is achieved after laser brazing. Tensile strengths of 418 and 373 MPa are obtained from laser brazed joints at the power of 800W and travel speed of 5 mm/s using Ti and Ti-15-3 fillers, respectively. All laser brazed joints are fractured at the brazed zone and cleavage dominated fractures are widely observed from their fractographs. The Ti base fillers show potential in laser brazing Mo substrate.