• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.47-51
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• 2016

It has made a special study of bending behavior of F.R.P. sandwich beams with bonded 2nd-reinforced plies. Specimen's faces were made of chopped mat 300-450, roving clothes 570, core is urethane foam, resin is 713bp unsaturated polyester for ship construction and the mixture weight ratio of resin versus fiber was 55:45 for bending analysis. The purpose of this paper is to study the exact bending behavior of bonded area's deflection and stiffness depends upon various bonded F.R.P. (2nd reinforced ply) length and thickness on which covered joints and to find the optimum design for the sandwich structures. All results and suggestions are based on experiment and using thick face calculation.

• Journal of the Korean Magnetics Society
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• v.7 no.3
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• pp.146-151
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• 1997

Buffer (t $\AA$)/ CoFe(35$\AA$)/Cu (50$\AA$)/Co (35$\AA$) sandwiches prepared by dc magnetron sputtering on Corning glass substrates using the $Co_{90}Fe_{10}$ and Co layers with different coercivities. Dependence of magnetoresistance on the type and thickness of buffer layers, and on the thickness of Cu and the magnetic layers in buffer/ CoFe/Cu /Co sandwiches were investigated. Magnetoresistance ratio and saturation field $H_s$ increased as thickness of the buffer layer becomes thicker, then decreased smoothly after a maximum value. An improved filed sensitivity was realized with the $Ni_{81}Fe_{19}$ buffer layer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.337-341
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• 2004

This paper concerns the analytical modeling and dynamic analysis of advanced rotating blade structure implemented by a dual approach based on structural tailoring and viscoelastic materials technology. Whereas structural tailoring uses the directionality properties of advanced composite materials, the passive materials technology exploits the damping capabilities of viscoelastic material(VEM) embedded into the host structure. The structure is modeled as a composite thin-walled beam incorporating a number of nonclassical features such as transverse shear, warping restraint, anisotropy of constituent materials, and warping and rotary inertias. The VEM layer damping treatment is modeled by using the Golla-Mushes-McTavish(GHM) method, which is employed to account for the frequency-dependent characteristic o the VEM. The displayed numerical results provide a comprehensive picture of the synergistic implications of the application of both techniques, namely, the tailoring and damping technology on vibration response of thin-walled beam structure exposed to external time-dependent excitations.

• KSBB Journal
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• v.23 no.3
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• pp.213-218
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• 2008

The present study was to investigate the continuous production of alcohol using immobilized carrier manufactured by polymeric materials. Fermentation runs with a crushed rice, with constituents recovered from batch culture and with ones from continuous culture were thus compared. The performances of immobilized carrier were governed by sandwitched synthetic polymers, the evolution of the continuous culture was steadily governed by the production of alcohol in the lag time of batch culture. The main focus was set on the enhancement of the alcohol production by an newly-developed polymeric forms. This polymeric form led to a drastic increase of the microorganism and the production cost in the continuous reactor was thereby reduced. The sandwitched polymeric-formed carrier, which was resistant to external environments, serves as an interesting alternative to maintain the stability of biological process. These whole results were discussed with the aim to better understand the continuous process implied in the microorganism's build-up during cultivation of fermentation broth.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.692-697
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• 2005

A canard type aircraft, which has good wing stall and stall/spin proof characteristics, is being developed. The previous first and second prototypes, having full depth core sandwich type wing and fixed landing gear, was built for test flights. Newly developing Firefly will be equipped with retractable landing gear and conventional foam core sandwich laminate for wing and fuselage. For manufacturing, composite material process has been studied including coupon tests. Wet lay-up onto foam core with glass fabric using lay-up mold has been chosen, and composite material parts are cured under room temperature and atmospheric pressure condition. In general, molded parts show so good surface smoothness and standardized quality that are best in mass production. In this study, we present the mold technology and development status for small aircraft firefly.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.101-109
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• 2002

The aluminum honeycomb sandwich panel (AHSP) structure not only have high flexural rigidity and strength per density but also excellence in vibration and noise properties. The AHSP structure are very useful for railway, airplane and high speed ship which need lighter-weighted and more strengthened elements. In this paper, from comparison the AHSP with the equivalent aluminum single plate (EASP) structure on the result of analysis, it was shown that the AHSP is S times lighter weight to the same stiffness than the EASP. And the AHSP structure have high bending rigidity and small shear rigidity in the direction of the thickness. Also, to the characteristics of vibration for the AHSP and EASP, which the stiffness is larger than the EASP, are higher than EASP.

• Journal of Industrial Technology
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• v.17
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• pp.191-197
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• 1997

For each construction material used, there is certain theoretical limit in sizes. For tall building construction, the reduction in slab weight is the first step to take in order to break such size limits. In this paper, the feasibility of such objective is proven and given by numerical analysis result. For a typical building slab, both concrete and advanced composite sandwich panels are considered. The concrete slab is treated as a special orthotropic plate to obtain more accurate result. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper. The influence of the modulus of the foundation on the natural frequency is thoroughly studied.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.120-125
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• 2000

A heddle frame is the major part of a loom that produces woven cloth by insertion of weft yarns between warp yams. Warp yarns are manipulated by many heddles fixed in a heddle frame. Recently, the up and down speed of heddle frames has been increased much for the increase of productivity, which induces higher inertial stresses and vibrations in the heddle frame. The heddle frame has the rectangular cross-section. For the design of box type beams of rectangular cross-section, extensional stiffness EA, flexural stiffness El, and torsional stiffness GJ as well as the vibration characteristics are important and should be simultaneously considered. Tn this paper, the vibration characteristics of the composite and the composite sandwich beams for high-speed heddle frame were tested by impulse frequency response.

• Journal of Korean Association for Spatial Structures
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• v.14 no.4
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• pp.65-72
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• 2014

To improve the noise and vibration problems of the existing public parking systems, new floor system was proposed. This system consists of the Sandwich Plate System(SPS), steel beam and post-tensioned steel tendons. To verify the dynamic characteristics such as the natural frequency and damping ratio of the system, the free vibration test was performed. Test results showed that the natural frequency of the SPS composite beam was 23.8Hz and it was increased by 3.8% by installing the post-tensioned tendons. The damping ratio of the specimen with tendons was about 1.64%.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.189-196
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• 2001

Machine tools of high-speed and high-precision are required for various fields of industry such as semiconductor, automobile, mold fabrication and so on. Light-weight machine tool structure is essential for reduction of production time through rapid transportation. Also, high damping capacity of the structure is required to obtain precise products without vibration during manufacturing. Composite materials have high potential for machine tool structures due to its high specific stiffness and good damping characteristics. In this study, the design and the manufacture of a hybrid machine tool structure using composite materials was attempted and the damping capacity was investigated experimentally.