• 한국생산제조학회지
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• 제18권3호
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• pp.270-278
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• 2009

Friction stir welding is a relatively new solid state joining process. A6061-T6 and A5052-H32 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. This friction stir process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, etc., and tool pin profile play a major role in deciding FSP zone formation in A6061-T6 and A5052-H32 aluminium alloy. Three different tool pin profiles have been used to fabricate the dissimilar butt joints. The formation of friction stir processed zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the friction stir processed zone formation.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.22-28
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• 2008

Friction stir welding(FSW) is an relatively new solid state joining process. A1606l-T6 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. This friction stir process(FSP) uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, etc., and tool pin profile playa major role in deciding FSP zone formation in A16061-T6 aluminium alloy. Tow different tool pin profiles have been used to fabricate the joints. The formation of friction stir processed zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the friction stir processed zone formation.

• Structural Engineering and Mechanics
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• 제14권5호
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• pp.565-574
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• 2002

This paper presents a method for predicting premature separation of carbon fiber reinforced plastic (CFRP) plates from strengthened steel beams. The fracture criterion based on material-induced singularity is formulated in terms of a singular intensity factor. Static test on double strap joints was selected to provide the critical stress intensity factor in the criterion because good degree of accuracy and consistency of experimental data can be expected compared with the unsymmetrically loaded single lap joints. The debond/separation loads of steel beams with different CFRP lengths were measured and compared with those predicted from the criterion. Good agreement between the test results and the prediction was found.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.258-263
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• 2001

In this paper, the real-time prediction of high temperature creep life was carried out for the friction welded joints of dissimilar heat resistintg steels (CulCr0.5Zr-STS316L). Various life prediction methods such as LMP (Larson-Miller Parameter) and ISM (initial strain method) were applied. The creep behaviors of those steels and the welds under static load were examined by ISM combined with LMP at 300, 400 and 50$0^{\circ}C$, and the relationship between these two methods was investigated. A real-time creep life (tsub/r/, hr) prediction equation by initial strain ($\varepsilon_0$, %) under any creep stress ($\sigma$, MP$\alpha$) at any high temperature (T, K) was developed

• International Journal of Automotive Technology
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• 제6권3호
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• pp.285-291
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• 2005

In this paper, the author proposes a fatigue damage parameter of spot welded joints under proportional loading. The proposed fatigue damage parameter is developed based on von Mises' equivalent stress and local structural stress at the edge of spot weld nugget. The structural stress at the edges of the weld nugget in each sheet is calculated using the forces and moments that are determined by finite element analysis. A structural equivalent stress is then calculated by von Mises' equivalent stress equation. The structural equivalent stresses are correlated to experimental fatigue life of the spot welded joints. The proposed parameter is evaluated with fatigue test data of spot welds subjected to multi axial and tensile-shear loads. Sheppard's parameter and Rupp and co-workers' parameter are also evaluated with the same test data to compare with the author's parameter. This proposed parameter presents a better correlation with experimental fatigue data than those of Sheppard's and Rupp and co-workers' parameter. The proposed parameter should be very effective for durability calculations during the early design phase since coarsely meshed finite element models can be employed.

• Structural Engineering and Mechanics
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• 제5권5호
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• pp.625-634
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• 1997

Reinforced concrete (RC) interior beam-column joints with high-strength materials: concrete compressive strength of 100 MPa and the yield strength of longitudinal bars of 685 MPa, were analyzed using three-dimensional (3-D) nonlinear finite element method (FEM). Specimen OKJ3 of joint shear failure type was a plane interior joint, and Specimen 12 of beam flexural failure type was a 3-D interior joint with transverse beams. Though the analytical initial stiffness was higher than experimental one, the analytical results gave a good agreement with the test results on the maximum story shear forces, the failure mode.

• 전자공학회논문지A
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• 제31A권12호
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• pp.44-55
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• 1994

This study is to apply the theory of fatigue fracture to solder joints under thermal cyclic loading and predict life of solder joint to failure. A 62Sn-36Pb-2Ag solder was used in this study. Tensile tests were preformed at temperatures of 15.dec. C, 50.dec. C and 85.dec. C in order to find terms of crack length "a". plastic strain range ""${\Delta}{\varepsilon}_p$" and temperature "T". Solder joint under thermal cyclic loading was analyzed by FEM. this FEM analysis together with the crack growth rate will provide the capability of the fatigue life prediction of solder joints and enhance the reliability od solder joint.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1639-1646
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• 2001

It is often necessary that the joints characteristics should be determined in the early stage of the vehicle body design. The researches on identification of joints in a vehicle body have been performed until the recent year. In this study, the joint characteristics of vehicle structure were expressed as the condensed matrix forms from the full joint stiffness matrix. The condensed joint stiffness matrix was applied to typical T-type and Edge-type joints, and the usefulness was confirmed. In addition, it was applied to the real center pillar model and the full vehicle body in order to validate the practical application.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.409-412
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• 2003

Fatigue strength. especially crack initiation behavior of high strength steel under marine water environment was investigated. Marine structures were usually constructed by lot of weld joints and were designed by basis of the fatigue strength of weld joints. This study was carried out to mini. The fatigue initiation behavior is more important rather than crack propagation behavior under the design of marine structures, because it is very difficult to find out the crack propagation phenomena and repair the damaged part of welded joints in sea water Then, the new configuration specimen for fatigue crack initiation tests was proposed. Using this new specimen, it is easy to carry out the crack initiation tests with relatively low cycling loading and clearly find out a crack initiation fatigue life.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.265-270
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• 2000

AESTRACI: The shmr behior of sawtoothed artrjicial joints grouted with cement milk rm investiguted in the lahotconstant normal stress conditions. Tests were amducted on joints with asperities h i n g inclinations cf 16.7" and 26.6" ,strengths h i n g 15MPa and 47MPa under a given nmge of n o d stresses wrying frcm 0.76 to 1.g MPa md at a freepitching, rolling and dihtmuy. Results show that the gect of asperities on shmr strength increme is signifamt up to as,to grout thidness (t/a) mtio 4 0.3-1.0. Increme of ahesim is the nmn muse cf shmr strength increme in cemmtoothed artificial iointsed artificial ioints