• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.118-121
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• 2008

Flexible die is more efficacious than fixed die which is generally used in stretch forming process in view of production cost. Accordingly, in order to verily the validity of the flexible forming process, curved thin skin structure forming analyses using the fixed and flexible die were performed. As results, merit and demerit with regard to the fixed and flexible die were confirmed. The result of the stretch forming process analysis using the flexible die was better than that using the fixed die in view of the elastic recovery. However wrinkles were occurred on the sheet material due to die cavities between the punches in the flexible forming process, thus the solutions against these problems were presented.

• 대한기계학회논문집 C: 기술과 교육
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• 제3권2호
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• pp.97-106
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• 2015

Flexible structures are often important components of mechanical assemblies in motion. A flexible structure sometimes must go through assembly steps that cause it to be in a pre-stressed condition when in the starting position for operation. A virtual prototype of the assembly must also bring the model of the flexible structure into the same pre-stressed condition in order to obtain accurate simulation results. This case study is presented regarding the simulation of a constant velocity joint, with a focus on the flexible boot. The case study demonstrates that careful definition of the initial conditions of the boot and flexible body contacts yields high-fidelity simulation results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.244.1-244.1
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• 2016

Recently, the technology for flexible electronics such as flexible smart phone, foldable displays, and bendable battery is under active development. With approaching the real commercialization of flexible electronics, the electrical and mechanical reliability of flexible electronics have become significantly important because they will be used under various mechanical deformations such as bending, twisting, stretching, and so on. These mechanical deformations result in performance degradation of electronic devices due to several mechanical problems such as cracking, delamination, and fatigue. Therefore, the understanding of relationship between mechanical loading and electrical performance is one of the most critical issues in flexible electronics for expecting the lifetime of products. Here, we have investigated the effect of monotonic tensile and cyclic deformations on metal interconnect to provide a guideline for improving the reliability of flexible interconnect.

• 대한기계학회논문집A
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• 제26권2호
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• pp.267-274
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• 2002

Using a flexible rotating beam test bed, experimental verification of a flexible multibody dynamic simulations for a rotating beam model has been carried out. The test bed consists of a flexible arm, harmonic driver reducer, AC servo motor and DSP board with PC. The mechanical ports of the test bed has been designed using 3D CAD program. For the simulation model, mass and moment of inertia of each part of the flexible rotating beam test bed are also obtained from 3D CAD model. In the flexible multibody dynamic simulations, the substructuring model has been established to capture nonlinear effects of the flexible rotating beam. Through the experimental verification, substructuring model provides better results than those from the linear model in the high speed rotation.

• 가정과삶의질연구
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• 제30권2호
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• pp.173-187
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• 2012

This qualitative case study focused on the activation plan of flexible work arrangements. We selected eight workers from a foreign affiliated firm that has various flexible work arrangements for in-depth interview and focus group interview. The workers were categorized into two groups; those who have experiences with flexible working and those who have needs for flexible working. We analyzed their condition of work-family life and experiences with flexible working. Through the focus group interview, we can find out the needs and suggestions about activation plans of flexible work arrangements.

• 마이크로전자및패키징학회지
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• 제20권4호
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• pp.1-6
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• 2013

Recently, various types of flexible devices such as flexible displays, batteries, e-skins and solar cell panels have been reported. Most of the researches focus on the development of high performance flexible device. However, to realize these flexible devices, the long-term reliability should be guaranteed during the repeated deformations of flexible devices because the direct mechanical stress would be applied on the electronic devices unlike the rigid Si-based devices. Among various materials consisting electronics devices, metal electrode is one of the weakest parts against mechanical deformation because the mechanical and electrical properties of metal films degrade gradually due to fatigue damage during repeated deformations. This article reviews the researches of fatigue behavior of thin metal film, and introduces the methods to enhance the reliability of metal electrode for flexible device.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.223-227
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• 2003

A new flexible electronic packaging technology and its medical applications are presented. Conventional silicon chips and electronic modules can be considered as "mechanically rigid box." which does not bend due to external forces. This mechanically rigid characteristic prohibits its applications to wearable systems or bio-implantable devices. Using current MEMS (Microelectromechanical Systems) technology. a surface micromachined flexible polysilicon sensor array and flexible electrode array fer neural interface were fabricated. A chemical thinning technique has been developed to realize flexible silicon chip. To combine these techniques will result in a realization of truly flexible sensing modules. which are suitable for many medical applications.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.825-828
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• 2005

Experimental and numerical study was done to confirm the effect of the flexible tube in pipeline on transient flow oscillation. Experiment was made for a pipeline with and without deformable flexible tube using a single pumping system of main stainless pipe. The wave speeds of main pipe and flexible tube were calculated from the pipe material properties, structures, and boundary conditions. Time dependent pressure fluctuations were calculated for the pipeline using the simple and the Kelvin-Voigt viscoelastic models for the deformation of main pipe and flexible tube. Pressure calculated by the Kelvin-Voigt viscoelastic model showed better agreement with measured one than pressure by the simple model. Experimental and numerical results show that the maximum pressure as well as amplitude of pressure oscillation was decreased by inserting short flexible tube in pipeline. Hence, inserted short flexible tube to pipeline was found to be effective for the suppression of strong pressure oscillation. Moreover, the wave speed in pipe was discussed based on numerical and experimental results.

• 한국안전학회지
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• 제6권1호
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• pp.26-30
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• 1991

Flammability, and released toxic halogen gases during combustion about two kinds of flame-retardant flexible foam(F.R. flexible PV foam) were investigated. One of the above was F.R. flexible PU foam with the containment of halogen and the other was manufactured with pure flexible PU foam in aqueous solution of alumina trihydrate(ATH) and dried 4 hours at 10$0^{\circ}C$. Flammability by L.O.I and UL94 HF-1 of the two materials were similarly shown. And combustion gases were analyzed with GC-Mass. HCI, CI$_2$ and HF were detected at both halogen being contained F.R. flexible PU foam and ATH dolng one The reason, to find halogen gases from burning ATH-containing F, R. flexible PU foam which wasn't used for any halogenated F.R., could be considered as by using trichlorofluoromethane with blowing agent to make PU foam. The relative quanity of relesed halogen gases of F.R. flexible PU foam with the containment of halogen had been indicated tree times HCI and CI$_2$, two times HF than ATH containing, respectively.

• Structural Engineering and Mechanics
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• 제60권6호
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• pp.1079-1092
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• 2016

In this paper, an electromechanical integrated harmonic piezodrive system is proposed. The operating principle of the drive system is introduced. The equation of the relationship between the displacements of the flexible ring and the rotating angle of the rotor is deduced. Using the equation, the displacements of the flexible ring for the drive system and their changes along with the system parameters are investigated. The results show that the displacements of the flexible ring changes periodically along with the rotation of the vibrator; there are abrupt changes in the displacements of the flexible ring at some points where there are abrupt changes in the number of the mesh teeth pair; the length of the flexible ring, the excitation voltage, and the speed ratio have obvious effects on the displacements of the flexible ring. The results are useful for the design of the drive system. ;