• 펄프종이기술
• /
• 제38권4호
• /
• pp.68-75
• /
• 2006

Electromagnetic shielding sheet using the carbon and wood fiber mixture was manufactured in an effort to develop an electromagnetic shielding packaging material. Carbon fibers were cut into 5, 10, and 15 mm using the automatic cutting device and blown and dispersed using compression air passed through the fine nozzle. Then carbon fibers were slurried with water (0.1% consistency), and softwood kraft pulp along with cone starch were added. The wet mats were manufactured by dewatering in modified hand-sheet machine. The wet mats were pressed upto $4kgf/cm^2$ in the carbon and wood fiber mixture mat press. The wet mats were dried in the automatic controlled plate dryer. Investigation on the formation and surface structure of the newly developed carbon and wood fiber mixture electromagnetic shielding sheet were carried out using the scanning electron microscopy and the image analyzer. Finally electromagnetic shielding characteristics of the newly developed carbon and wood mixture sheet were measured using net-work analyser. The result was promising in the light of the fact that this method could open a new way to substitute the expensive imported electromagnetic shielding sheet.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
• /
• pp.250-253
• /
• 2004

Emphasis has been placed on thin plate fabrication of plain woven carbon fabric reinforced Al matrix composites using liquid pressing process. The composite has potential applications for PDP rear plate. The process is to use the low pressure for infiltration of Al melt into plain woven carbon fabric as the Al melt is pressurized directly. The minimum pressure required for the infiltration was calculated from force balance equation, permeability measurements and compaction behavior of carbon fiber. Also, the melting temperature and the holding time have been optimized. In order to measure coefficient of thermal expansion (CTE) of the composites, the thermal strain measurement using strain gage was performed and the thermal conductivity of the composites was measured using laser flash method. The constituent materials of the composite are PAN type carbon fibers as reinforcements and 6061 Al alloys as matrices.

• Structural Engineering and Mechanics
• /
• 제67권4호
• /
• pp.403-415
• /
• 2018

In the present study, nonlinear dynamic response of polymer-CNT-fiber multiscale nanocomposite plate resting on elastic foundations in thermal environments using the finite element method is performed. In this regard, the governing equations are derived based on Inverse Hyperbolic Shear Deformation Theory and von $K{\acute{a}}rm{\acute{a}}n$ geometrical nonlinearity. Three type of distribution of temperature through the thickness of the plate namely, uniform linear and nonlinear are considered. The considered element is C1-continuous with 15 DOF at each node. The effective material properties of the multiscale composite are calculated using Halpin-Tsai equations and fiber micromechanics in hierarchy. The carbon nanotubes are assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. Five types of impulsive loads are considered, namely the step, sudden, triangular, half-sine and exponential pulses. After examining the validity of the present work, the effects of the weight percentage of SWCNTs and MWCNTs, nanotube aspect ratio, volume fraction of fibers, plate aspect, temperature, elastic foundation parameters, distribution of temperature and shape of impulsive load on nonlinear dynamic response of CNT reinforced multi-phase laminated composite plate are studied in details.

• 한국생산제조학회지
• /
• 제9권4호
• /
• pp.34-47
• /
• 2000

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high specific modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles , spindles of machine tools, motor base, bearing mount for tool up and manufacturing. The molded composite machine elements are not usually accurate enough for mechanical machine elements, which require turning drilling , cutting and grinding. The experiment are surface grinding wheel GC60 to the carbon fiber epoxy composite specimen with respect to staking angle [0]nT , [45]nT, [90]nT on the CNC grinding machine. In this paper, the surface grinding characteristics of composite plate, which are surveyed experimentally and analytically with respect to the grinding force, surface roughness and wheel loading according to the variable depth of cut, wheel velocity and table feed rate are investigated.

• 오토저널
• /
• 제11권1호
• /
• pp.44-50
• /
• 1989

본 논문에서는 모우드 해석법(Modal Analysis Method)을 이용하여 종래 재료에 비해 우 수한 기계적 성질을 갖는 복합재료에 대하여 동특성을 규명하고자 하였다. 재료로는 알루미늄 판(AL PLATE)과 탄소섬유강화 복합적층판(CFRP)을 비교하였으며, 그 결과 전체적인 진동레 벨이 AL PLATE 보다 CFRP PLATE가 낮았고 섬유방향이 고정단고 직각인 경우보다 평행인 경우가 낮음을 알았다. 또한 AL PLATE와 유사한 진동형을 나타내는 CFRP PLATE의 고유 진동모우드가 저주파수쪽으로 이동함을 알 수 있었다.

• 비파괴검사학회지
• /
• 제6권1호
• /
• pp.23-30
• /
• 1986

The optimumultrasonic test conditions for the thin carbon fiber reinforced plastic (CFRP) sheet were determined for the immersed reflector plate method. The effects of the water distance, the surface conditions of the specimen and transducer characteristics were studied. For a reliable test the water distance between the transducer and the front surface of the specimen should be determined when the beam profile of the transducer appears in the bell-shape. The detectability of the defect was improved as the effective beam width of the ultrasonic transducer became narrow. The transducer should be properly chosen considering to the surface condition of the test material as well as the size and type of the defect to be detected. It was possible to detect the flat bottom hole whose diameter is as small as about 500 micrometer.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
• /
• pp.727-732
• /
• 2000

Recently, Carbon Fiber Reinforced Plats are widely used to strength the RC beams. But the behaviour of the RC beams which is strengthened with the CFRP is not clearly defined yet. So, this experimental study was carried out for reinforced concrete beams with epoxy-bonded CFP plates. This study is selected experimental variables which are strengthening plate length, pre-loading before reinforcement and the method of anchoring the plate ends. This study investigates was strengthening effect of the RC beams by adhesion of the CFRP, and CFRP as to the respective variables.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.180-183
• /
• 2009

Composite bipolar plates offer several advantages of low cost, light weight, and ease of manufacturing compared to traditional graphite plate. However, it is difficult to achieve both high electrical conductivity and high flexural strength. In this study, the hybrid carbons filled epoxy composite bipolar plates were fabricated to test electrical conductivity and flexural properties. Graphite powders were used as the main conducting filler and continuous carbon fiber fabrics were inserted to improve the mechanical properties of the composite. This hybrid composite showed improved in-plane electrical conductivity and flexural property. The moldability of the hybrid composite was also improved comparing to the continuous prepreg composite. This study suggested that the continuous carbon fiber inserted graphite/epoxy composites can be a potential candidate material to overcome the disadvantages of conventional graphite composite or continuous prepreg composite bipolar plates.

• 대한기계학회논문집
• /
• 제18권8호
• /
• pp.2123-2138
• /
• 1994

A study on the dynamic mechanical properties of the high strength carbon fiber epoxy composite beam was carried out. The macromechanical model was used for the theoretical analysis of the symmetric laminated composite beam. The anisotropic plate theory and Bernoulli-Euler beam theory were used to predict the effective flexural elastic modulus and the specific damping capacity of laminated composite beam. The free flexural vibration and torsional vibration tests were carried out to determine the specific damping capacities of the unidirectional laminated composite beam. The vibration tests were performed in a vacuum chamber with laser vibrometer system and electromagnetic hammer to obtain accurate experimental data. From the computational and experimental results, it was found that the theoretical values with the macromechanical analysis and the experimental data of symmetric laminated composite beam were in good agreement.

• Steel and Composite Structures
• /
• 제28권4호
• /
• pp.495-508
• /
• 2018

In this paper, the effect of matrix cracks on the buckling of a hybrid laminated plate is investigated. The plate is composed of carbon nanotube reinforced functionally graded (CNTR-FG) layers and conventional fiber reinforced composite (FRC) layers. Different distributions of single walled carbon nanotubes (SWCNTs) through the thickness of layers are considered. The cracks are modeled as aligned slit cracks across the ply thickness and transverse to the laminate plane, and the distribution of cracks is assumed statistically homogeneous corresponding to an average crack density. The first-order shear deformation theory (FSDT) is employed to incorporate the effects of rotary inertia and transverse shear deformation, and the meshless kp-Ritz method is used to obtain the buckling solutions. Detailed parametric studies are conducted to investigate the effects of matrix crack density, CNTs distributions, CNT volume fraction, plate aspect ratio and plate length-to-thickness ratio, boundary conditions and number of layers on buckling behaviors of hybrid laminated plates containing CNTR-FG layers.