• Composites Research
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• v.17 no.6
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• pp.28-36
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• 2004

Micro-tow deformation during forming of PVC foam-fabric composite sandwich structure is investigated to find out the correlation between forming condition and material deformation. The foams used in this research are PVC foams which have 4 different densities and the fabric composite is Carbon/epoxy prepreg which is plain weave (3k) as a skin material. Tow parameters such as crimp angle and tow amplitude are measured using microscope and a proper image tool and are compared with each other. In order to find out the effect of foam deformation during forming on tow deformation the compressive tests of foams are performed in three different environmental temperatures ($25^{\circ}C$, $80{\circ}C$, $125^{\circ}C$). The microscopic observation results show that the micro tow deformations are quite different from each other with respect to the foam density and forming pressure.

• Composites Research
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• v.16 no.4
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• pp.29-35
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• 2003

In this paper. various tow parameters such as equivalent tow thickness, amplitude of longitudinal tow and tow intervals were investigated and compared with each other by using microscopic observation to find out the exact deformation patterns between both directions of the fabric structure(Longitudinal and Transverse Directions). And those observation results were compared with bias extension. biaxial tests results with dry fabric which has the same tow structure as the draped helmet materials and also compared with prepreg specimen which is cured by autoclave moulding without vacuum and pressure condition. Specimens for the observation were taken from draped helmet which is made of fabric composite(Five Harness Satin Weave). From the observation results, it was found that there are different deformation pattern between tow directions and effect of geometric condition on the deformation of the fabric materials during draping process was verified.

• Composites Research
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• v.17 no.1
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• pp.38-46
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• 2004

This paper aims to correlate the micro-mechanical behaviour of tow geometry with applied in-plane forces during deformation of dry woven carbon-fibre fabric. These in-plane forces lead to differences in tow reorganisation during deformation and so changes in the way in which 'lock-up' occurs. In this paper, deformation of micro-mechanical parameters such as tow interval, crimp angle, change in tow amplitude and wavelength are investigated. To observe the micro-deformation of the fabric structure, appropriate specimens from bias extension and biaxial tests are sectioned and observed under the microscope. It was found that different loading conditions cause geometric deferences in the tow architecture. The variation in deformed tow geometry with shear angle is fitted using a simple parametric model.

• Economic and Environmental Geology
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• v.45 no.4
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• pp.465-476
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• 2012

The Anatolia peninsula consists of several continental fragments that include the Pontide Block in north and the Anatolide-Touride Block in south as well as the Arabian Platform in southeast. These continental blocks were joined together into a single landmass in the late Tertiary. During most of the Phanerozoic these continental blocks were separated by paleo-oceans, such as Paleo-Tethys and Neo-Tethys. The Pontide Block in north show Laurasian affinities, and was only slightly affected by the Alpide orogeny; they preserve evidence for the Variscan and Cimmeride orogenies. The Pontic Block is composed of the Strandja, Istanbul and Sakarya zones that were amalgamated into a single terrane by the mid Cretaceous times. The Anatolide-Tauride Block in south shows Gondwana affinities but was separated from Gondwana in the Triassic and formed an extensive carbonate platform during the Mesozoic. The Anatolide-Tauride Block was intensely deformed and partly metamorphosed during the Alpide orogeny; this leads to the subdivision of the Anatolide-Tauride Block into several zones on the basis of the type and age of metamorphism and deformation. The Arabian Platform in southeast forms the northernmost extension of the Arabian Plate that shows a stratigraphy similar to the Anatolide-Tauride Block with a clastic-carbonate dominated Palaeozoic and a carbonate dominated Mesozoic succession. A new tectonic era started in Anatolia Peninsula in the Oligocene-Miocene after the final amalgamation of these continental blocks and plate. This neotectonic phase is characterized by extension, and strike-slip faulting, continental sedimentation, and widespread calcalkaline magmatism, which played a very important role in producing beautiful landscapes of the Anatolia Peninsula today.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.198-201
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• 2004

This paper aims to investigate the micro-mechanical behaviour of tow geometry with forming pressures and densities of foams during the curing process of plain weave carbon fibre fabric prepregs onto polymer foams. In order to find out and compare deformation patterns between different forming conditions, tow parameters such as amplitude and crimp angle etc. are investigated. From the observation results, geometric difference in the tow architecture with respect to forming conditions and foam characteristics were found. To observe the micro-deformation of the fabric structure, appropriate specimens from carbon fibre-foam sandwich structures are sectioned and observed under the microscope.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.16-22
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• 2012

The use of welding process has been increased for manufacture of machine, bridges, ships, gas facilities and so on together with development of welding technique. Accordingly, it has been needed to develop the welding methods considering higher productivity and safety design for manufacture of their welding structures. In this study, it was studied basically on characteristics of fatigue strength and fatigue life in full penetrated cruciform fillet weld zone in relation to material thickness, welding passes, loading direction and notch radius of toe zone. Most of fatigue failure occurred in toe zone of cruciform fillet weld joint. Fatigue strength and fatigue life are under the influence of stress concentration due to notch radius and flank angle of toe zone. The metal of toe zone annealed and diffused by multi-layer welding and acicular ferrite structure formed by the result improved fatigue strength and fatigue life.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.154-157
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• 2005

This paper aims to investigate the tow deformation pattern with respect to shear angle and mold property during draping of plain weave carbon/epoxy prepreg. Aluminum and PVC foams with different foam density are used for the draping hemisphere molds with 250 mm diameters. Microscopic observation reveals that tow parameters like crimp angle and Y-directional tow intervals are influenced by shear angle and mold density at the same time. The correlation between crimp angle and Y-directional tow interval is also found out.

• Composites Research
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• v.30 no.1
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• pp.26-34
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• 2017

This research presents studies on an improved method to predict the thermal conductivity of woven fabric composites, the effects of geometric structures of woven fabric composites on thermal conductivity, and structural optimization to improve the thermal conductivity using a genetic algorithm. The geometric structures of woven fabric composites were constructed numerically using the information generated on waviness, thickness, and width of fill and warp tows. Thermal conductivities of the composites were obtained using a thermal-electrical analogy. In the genetic algorithm, the chromosome string consisted of thickness and width of the fill and warp tows, and the objective function was the maximum thermal conductivity of woven fabric composites. The results confirmed that an improved method to predict the thermal conductivity was built successfully, and the inter-tow gap effect on the composite's thermal conductivity was analyzed suggesting that thermal conductivity of woven fabric composites was reduced as the gap between tows increased. For structural design, optimized structures for improving the thermal conductivity were analyzed and proposed. Generally, axial thermal conductivity of the fiber tow contributed more to thermal conductivity of woven fabric composites than transverse thermal conductivity of the tows.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.220-226
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• 2003

This paper presents the result of an investigation on the application of the acoustic emission method to the monitoring of fatigue crack initiation, growth and track location in welded joints. Fatigue test was carried out for a typical fillet welded joint of ship structure. AE parameter such as ring down count was analyzed in time domain and crack locations were examined by source location and cluster option which is one of the functions of AE signal processor The usability of AE mettled was confirmed for the detection of the initiation and location of through crack.

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.549-556
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• 1988

In order to study the changes for the structure of N-benzylisonitrosoacetylacetone imine synthesized already in organic solution, nmr and carbon-13nmr DEPT spectra of the this reagent have been studied. Based on the present studies, it is suggested that this reagent is monoxime having syn- and anti-form isomers and has tautomers in solution respectively.