• 한국공작기계학회논문집
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• 제10권4호
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• pp.91-96
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• 2001

In this paper, an investigation was performed on the dynamic interlaminar fracture toughness of CFRP(carbon filber rein-forcement plastics). Specimens used in this experiments are CF/PEEK laminated plates. In this experiments, Split Hopkin-sons Bar(SHPE) tes was apply to dynamic and notched flexure test. The model II fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-integral with the measured impulsive load and reac-tions at the supported points. As an experimental results the vibration amplitude of [$0^{\circ}_10 /F_4 0^{\circ}_10 $] j-aminates appear more than that of [$0^{\circ}_10 /F_2 0^{\circ}_10 $ laminates for the j-integral and displacement velocity at a measuring point. Also, it is thought that the dynamic fracture toughness of two kind specimen(CF/PEEK) with the crease of displacement velocity becomes great at a measuring point with in the range of measurement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.96-100
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• 1997

The shadow moire is one of the optical techniques which is able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a master grating and its shadow projected on the surface of an object. In case of the classical shadow moire method, the sensitivity was a few tenths millimeters. generally, it is difficult to use a phase shift method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study we use the fact that if the depth of object is much less than the distance between the observer and the master grating, and the object is displaced perpendicularly to the grating plane, phase shifts are almost uniform. Finally we obtained a better resolution by using a phase shift procedure and applied the phase shifting shadow moire to three dimensional shape measurement.

• 한국안전학회지
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• 제13권4호
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• pp.41-48
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• 1998

In this paper, an investigation was performed on the dynamic interlaminar fracture toughness of CFRP(carbon fiber reinforcement plastics) composite laminates. Composite laminates used in this experimentation are CF/EPOXY and CF/PEEK laminated plates. In the experiments, Split Hopkinson's Bar(SHPE) test was applied to dynamic and notched flexure test. The mode Ⅱ fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-integral with the measured impulsive load and reactions at the supported points. As an experimental result, the vibration amplitude of CF/PEEK laminates appear more than that of CF/EPOXY laminates for the J-integral and displacement velocity at a measuring point. Also, it is thought that the dynamic fracture toughness of two kind specimens(CFRP/EPOXY and CF/PEEK) with the in crease of displacement velocity becomes a little greater at a measuring point within the range of measurement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.675-678
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• 2001

In this paper, an investigation was performed on the dynamic interlaminar fracture toughness of CFRP(carbon fiber reinforcement plastics). Specimens used in this experiment are CF/EPOXY laminated plates. In this experiments, Split Hopkinson s Bar test was applied to dynamic and notched flexure test. The mode II fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-integral with the measured impulsive load and reactions at the supported points. As an experimental result, the vibration amplitude of 〔$0_{10}F_4/0_{10}$〕laminates appear more than that of 〔0_{10}/F_2/0_{10}$〕laminates for the J-integral and displacement velocity at a measuring point. Also, it is thought that the dynamic fracture toughness of two kind specimen with the increase of displacement velocity becomes great at a measuring point with in range of measurement.

• 전자공학회논문지D
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• 제34D권7호
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• pp.56-61
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• 1997

I $n_{0.53}$G $a_{0.47}$As/I $n_{0.52}$A $l_{0.48}$As pseudomorphic high electron mobility transistor (P-HEMT) structures were grown on semi-insulating InP substrates by molecular beam epitzxy method. The hall effect measuremetn was used to measure the electrical properties and the photoluminescence (PL) measurement was used to measure the electrical properties and the photoluminescence(PL) measurement for optical propety. By the cross-sectional transmission electron microscopy (XTEM) investigation of the V and X shape defects including slip with angle of 60.deg. C and 120.deg. C to surface in the sampel, the defects formation mecahnism in the I $n_{0.52}$A $l_{0.48}$As epilayers on InP substrates could be explained with the different thermal expansion coefficients between I $n_{0.52}$A $l_{0.48}$As epilayers and InP substrate.d InP substrate.