• Journal of Welding and Joining
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• v.19 no.3
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• pp.342-347
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• 2001

Recently, adhesive-bonding technique is wifely used in manufacturing structures. Stress and strain analysis of joints are essential to design adhesive-bonded joints structure. The single-lap adhesive joint is the design dominating the range of adhesive joints. In this study, single-lap specimens with different joint dimensions were used for the tensile-shear test and finite element calculation in of order to investigate the effect of overlap length and adhesive-bonding thickness on adhesive strength and stress distribution of the joints. Consequently, it was found that overlap lap size and thickness can be important parameters of structure joints using adhesive bonding, which is effected on adhesive strength.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.263-270
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• 2003

Before the implementation of the 1992 seismic design provisions in Korea, longitudinal steels of RC bridge piers were practically lap-spliced in the plastic hinge region. Experimental investigation was made to evaluate the seismic performance of RC bridge pier specimens in a flexure/shear mode. Six circular test specimens in an aspect ratio of 2.5 (600mm in diameter) were made with test parameters confinement ratio, lap splices, and retrofit FRP materials. They were damaged under a series of artificial earthquakes with 0.22g PGA, being compatible in Korean peninsula, through the pseudo-dynamic test. Probable damages were assessed by the Park and Ang damage index. Approximate 0.1 and 0.3 damage indices were obtained for RC specimens without lap splice and with lap splice, respectively. Directly after the pseudo-dynamic test, damaged test columns were laterally actuated under inelastic reversal cyclic loadings simultaneously under a constant axial load. Through curvature measurements, residual seismic performance was evaluated for test specimens. Test results show that RC pier specimens with lap-spliced appeared to fail at low ductility, but significant improvement was obtained for the ductility of these specimens if externally wrapped with FRP.

• International Journal of Advanced Culture Technology
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• v.3 no.1
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• pp.145-152
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• 2015

The article aims to apply a friction stir spot welding for producing the lap joint between AA5052 aluminum alloy and C11000 copper alloy. The dimension of the materials was 100 mm in length, 30 mm in width and 1.0 mm in thickness. The copper plate was set overlap the aluminum plate by 30 mm. The welding parameter was the rotating speed of 2500-4000 rpm, the pin inserting rate of 2-8 mm/min and the holding time of 6 sec. The mechanical properties test and the microstructure investigation were performed to evaluate the lap joint quality. The summarized results are as follows. The friction stir spot welding could produce effectively the lap joint between AA5052 and C11000 copper. Increase of the rotating speed and holding time directly affected to decrease the tensile shear strength of the lap joint. The optimized welding parameters in this study that indicated the tensile shear strength of 864 N was the rotating speed of 3500 rpm, the pin inserting rate of 6 mm/min and the holding time of 4sec. The experimental results also showed that the hardness of the weld metal was lower than that of the base materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.334-339
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• 2020

In this study, the adhesion properties between aluminum and composite materials, composite materials, and composite materials were compared according to the physical surface treatment to improve mechanical bonding at the bonding surface when considering carbon fiber and glass fiber-reinforced composite materials. Bonded specimens were classified into the type of base material and the surface treatment method of the bonding surface. Sandpaper, sandblasting, and plasma were applied as physical surface treatment methods. The bonded specimen was prepared as a single lap joint test specimen. An experiment to measure the lap shear strength was conducted, and the results were compared. The experimental results confirmed that the mechanical abrasion and sandblasting treatment improved the lap shear strength approximately 4 to 5 fold compared to the general specimen without physical surface treatment. In plasma treatment, the experiment was conducted by defining the respective plasma output and treatment time as follows: 150 W and 5 minutes, 150 W and 10 minutes, and 300 W and 3 minutes. Moreover, the lap shear strength results were similar to the previous mechanical surface treatments. On the other hand, the effect on the adhesion properties was small, depending on the plasma treatment conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.53-64
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• 2012

Deep and narrow welds can be produced by laser welding at high welding speeds with a narrow heat-affected zone (HAZ) and little distortion of the workpiece. This study aims to evaluate the usefulness of laser welding at automobile component manufacture. Microstructure observation, hardness test, tensile test and fatigue life test are performed by using the fiber laser welded SPFC590 steel sheets which is used widely in the manufacture of automotive seat frame. Three kinds of specimens are only a SPFC590 steel plate, quasi-butt joint plate and lap joint plate by laser welding. The following results that will be helpful to understand the static strength, fatigue crack initiation and growth mechanism were obtained. (1) The tensile strength of quasi butt joint specimens nearly equal to base metal specimens, but lap joint specimens fractured in shear area of weld metal. (2) The fatigue strength of quasi-butt joint specimen was approximately 8 percent lower than that of the base metal specimens. Furthermore, the lap joint specimens were less than 86 percent of the base metal specimens. (3) The lap joint fatigue specimens fractured at shear area in high level stress amplitude, while fractured at normal area in low level stress amplitude. From these results, the applicability of the laser welding to the automobile component is discussed.

• Composites Research
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• v.23 no.1
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• pp.37-43
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• 2010

In this paper, we present the result of an experimental investigation pertaining to the structural behavior of bolted lap-joint connection of pultruded fiber reinforced plastic structural shapes. In the experimental investigation, in order to find the mechanical property of the material, tension and shear tests on the pultruded structural composite specimen are conducted prior to the investigation on the structural behavior of bolted lap-joint connection of the member. Based on the result, number of bolts, type of placement and location of bolt are determined to be a test variable. Three different types of experimental specimens are prepared. Tensile load is applied through the center of the specimen with lap-joint connection and the structural behavior and failure mode of the test specimens with respect to the tensile load increment are investigated. As a result, it is found that most of the failure mode at the lap-joint connection is shear failure mode. Consequently, it is also found that the data obtained through this experimental program could be used for the structure connection design as a basis.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.5
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• pp.41-53
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• 2012

The objective of this study is to evaluate the seismic capacity of RC piers with small aspect ratios. Test specimens were selected from the prototype piers among existing national roadway bridges which are expected to fail in shear and/or complex shear-flexural mode. Two groups of full scale RC pier models were constructed with aspect ratios of 2.25 and 2.67. Quasi-static tests have been implemented to investigate the failure behavior of the RC piers in terms of the lap-spliced longitudinal reinforcing steel and the aspect ratio. It is confirmed that regarding its shear-flexural behavior, the pier is very sensitive to the aspect ratio or details. In the case of a test pier with highly lap-spliced longitudinal bars, the bond failure of lap-splice steels was the dominant cause of failure before the occurrence of flexure or shear-flexural failure, despite a slight change in the aspect ratio. Finally, based on the test results and analysis, this paper proposes formulas for the yielding and ultimate displacements of circular reinforced concrete bridge piers without seismic details. These formulas will be useful for the investigation and upgrade of the seismic capacity of bridge piers without seismic details.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.127-133
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• 2020

It is important to measure the quantitative adhesive strength between an organic adhesive and a metal adherend. In measuring the adhesive strength between an organic adhesive and a metal adherend, the effect of the kind and thickness of the adherend on the adhesive strength was studied. Two kinds of metal adherends were selected, aluminum (Al1050) and stainless steel (STS304), and a dolly test and a lap shear test were used to measure the adhesive strength. When measuring the adhesive strength between the organic adhesive and the metal adherend by the tensile stress mode of dolly test, the change in the thickness of the metal adherend had little effect on the adhesive strength, however, the adhesive strength was different depending on the kind of the adherend. On the other hand, when measuring the adhesive strength between the organic adhesive and the metal adherend by the lap shear test, the change in the relative thickness of the metal adherend had an effect on the adhesive strength. The reason is that the bending phenomenon of the adherend occurring in the edge of bonding region during the lap shear test contributes to lowering the adhesive strength by generating additional tensile stress in the bonding region. From this work, it is concluded that the dolly test could be widely used when measuring the quantitative adhesive strength of organic adhesives and metal adherend because there is little change in adhesive strength even though the thickness of the adherend is changed.

• Journal of the Korean Wood Science and Technology
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• v.35 no.4
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• pp.38-44
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• 2007

As environmental issues is important thing, our study aims to develop natural adhesives made by rosin instead of synthesis adhesive with the formaldehyde emission. Natural adhesives were formulated to enhance curing speed and adhesion performances with various drying agent contents. Adhesion performances were evaluated with tack values measured by texture analyzer and shear strengths determined by single lap shear test. The adhesion performances of nature adhesives developed in this study and compared with those of overseas natural adhesives made by AURO, BioFa, Livos. Optimum drying agent formulation was Co 0.7 part, Zr 1.0 part, Ca 0.5 part, and Activ8 0.1 part. Shear strength of the adhesives manufactured by the optimum drying agent formulation was $93.2{\pm}19.1N/cm^2$.

• Laser Solutions
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• v.15 no.1
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• pp.1-5
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• 2012

Recently ultra high strength steels(UHSS) has been widely applied to the structural or safety components in the automotive industry. Specially, hot stamping boron steel 22MnB5 has shown the crash-resistant characteristics when applying to bumpers and pillars. Lap joint Laser welding of the hot stamped and die quenched sheets of Boron steel was carried out using 3kW Nd/YAG laser. The appropriate Lap joint laser welding conditions were founded separately for four lap joint combinations. The lower sheest is a hot stamped sheet in common and the upper sheet is selected among the hot stamped steel and high strength steels such as SPCC, 370MPa, and 590MPa grade high strength steels. Cross bead sections and local hardening and softening were observed as well as tensile-shear test results.