• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.710-715
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• 1997

This paper deals with the analysis of the optimum value of honeycomb core considering variable design parameter. As thickness and height of core rises in design parameter, natural frequency of laminated composite plate increases. The angle-phy has the maximum value when the plate of honeycomb core join to opposite direction. This paper shows that the natural frequency of CFRP was higher than that of GFRP and mode shapes were various at angle-ply.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.1
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• pp.88-93
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• 2001

Carbon fiber epoxy composite are widely used in airframe structures, space vehicles, sports equipment, and high speed reciprocating parts for industrial machinery. In this paper, the groove processing characteristics of carbon fiber epoxy com-posite was experimentally investigated in order to study the endmill operation of fiber reinforce epoxy composites. Followings are main finding from the experimental results. First, the cutting and bending force in groove processing of the carbon fiber epoxy composite increased as the spindle speed deceased. They also deceased as the table feed increased. Second, the good cutting status obtained at the entrance of groove while delamination occurred at the exit of groove, Third, the regular high speed steel endmill was not efficient, thus the new endmill such as coated carbide rooter endmill or dia-mode endmill should be used for the effective endmll operation of carbon filber epoxy composites.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.727-732
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• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.763-768
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• 2000

The purpose of this paper is to predict the flexural strengthening of reinforced concrete beams by the external bonding of carbon fiber reinforced plate(CFRP) to the tension face of the beam. Used computational equation is derived by relation of stress an strain. This equation is applied to four-nondamage beam and tow-preloading beam. Six scale beams were tested to evaluate the strength enhancement provided by the CFRP. And describes the strength enhancement provided to the flexural capacity of reinforced concrete beam by the external bonding of CFRP. An inelastic section analysis procedure was developed that accurately predicts the load displacement response of the retrofitted beams.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1660-1665
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• 2003

On this study, we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite cantilever plate by each aspect ratio. A finite element analysis on the CFRP laminated composite cantilever plate using orthogonal array is carried out, and the results are compared with those obtained by modal testing.

• Composites Research
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• v.12 no.5
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• pp.80-86
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• 1999

Mechanical characteristics of composite laminates and cylindrical shell using scrim of glass scrim are evaluated in this paper. Composite laminates and cylindrical shells are made by inserting carbon scrim or glass scrim between layers. The mechanical properties are routinely characterized by ASTM stands. Experimental results show that the mechanical properties of UD prepreg in the transverse direction are highly improved by inderting scrims between layers.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.04a
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• pp.189.1-192
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• 1999

Mechanical characteristics of composite laminates with carbon tissue and glass scrim are evaluated in this paper. Composite laminates in USN125 group are made by inserting carbon tissue and glass scrim between layers. Consequently it was shown that mechanical characteristics of carbon fiber reinforced composite materials were improved by inserting carbon tissue.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.892-895
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• 2002

In this study, to grasp the effect of vibration intensity fur the laminated composite plate, the two-dimension plate was shaken by a harmonic point excitation with the natural frequency using the finite element method. As the result, it shows that the vibration intensity according to the change of angle-ply is various and it flows to the direction of length rather than width in the plate. Also this paper represents those results to the vector flow.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.220-228
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• 1997

We discuss finite element approximation and use a Mindlin plate element based upon uniformly reduced numerical integration. The finite element selected for use in this work is a four-node, bilinear displacement element based upon the Mindlin theory of plates. Such elements show good accuracy for laminated composite plates when reduced numerical integration is used to evaluate the element marices. This study presents both the experimental and F.E. results for the natural frequencies of CFRPURETHANE-CFRP Composite plate. Good agreement between experimental and calculated frequencies is achived.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2518-2534
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• 1993

Fracture behavior of carbon/epoxy laminates under pin loading is studied experimentally and analytically. Effects of ratios of specimen width to hole diameter and edge distance to hole diameter on bearing strength are investigated. Characteristic length of the laminates obtained using HK model has good agreement with the experimental data. The larger hole size induced, the lower bearing strength is measured under pin loading . The bearing strength and failure mode could be predicted using HK model and Zhangs analytical solution of stress distribution around a pin loaded hole. Chamis' prediction method of bearing strength is also considered to predict failure mode and bearing strength. A modification of Chamis' method is made using the factor of rupturc. The predicted bearing strength by the modified method is reasonably close to the experimental data.