• Composites Research
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• 제24권2호
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• pp.1-8
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• 2011

복합재료/금속 접착 조인트의 파손기준을 제시하기 위하여 다양한 혼합모드 하중상태에서 계면파괴인성을 측정하였다. 계면파괴인성은 SLB 시편을 이용하여 측정하였으며 시편의 두께를 변화시킴으로 모드 혼합비율을 다양하게 설정하였다. 실험결과 계면의 파괴인성은 균열 열림에 비해 균열 미끄러짐 모드의 비율이 높은 하중상태에서 더 큰 값을 나타내었다. 균열 열림 및 미끄러짐 하중모드에 따른 계면파괴 거동의 차이를 균열진전 과정을 관찰한 현미경 영상을 기초로 고찰하였다. 표면 거칠기가 접착 강도에 미치는 영향 또한 고찰되었다.

• 대한기계학회논문집A
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• 제25권12호
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• pp.2070-2077
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• 2001

An experimental investigation of the effect of composite patching repair was conducted to characterize the fatigue crack growth behavior in thick A16061-T6 (6mm) panels with single bonded patch by fiber reinforced composite patch. Four patch lengths and no patch plate were examined. An analytical procedure, involving three-dimensional finite element method having three layers to model cracked aluminum plate, epoxy by adhesive and composite Patch, is calculated the stress intensity factors. From the calculated stress intensity factors, the fatigue crack growth rates are obtained. At the single patching type, different fatigue crack growth ratios through the palate thickness were investigated by using the experimental and analytical results. The results demonstrated that there was a definite variation in fatigue life depending on the size of composite patch. While crack reached the patch end, retardation of crack growth was also revealed in the bonded repair.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1531-1531
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• 2001

A novel technique has been developed to observe the three-dimensional (3-D) distribution of chemical components in biological materials using both automatic sectioning microtome and infrared microscope. The 3-D image was reconstructed based on the relationship between the content and the absorbancy of specified wavelength for chemical components. By using the automatic sectioning microtome, the kernel of rice sample fixed in paraffin was sequentially sliced with the thickness of $5\;\mutextrm{m}$ after pasting the sliced sectional specimens on an adhesive tape. The chemical components of the specimens, which are placed on the X-Y controlling stage with positioning accuracy of ${\pm}10\;\mutextrm{m}$, were analyzed by the infrared microscope. The 3-D images demonstrated that the zonal protein about $200\mutextrm{m}$ in width was observed mainly at the outer parts of a rice particle, and carbohydrates entirely. These images can be observed by choosing arbitrary observation angle. The result indicated that the developed technique could be applied 3-D information to investigate intrinsic chemical components but also residual pesticides as well as bacteria contamination for agricultural produce.

• 대한기계학회논문집
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• 제17권8호
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• pp.2061-2068
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• 1993

Condition monitoring technology is of great importance for the maintenance of complex machinery in view of its early monitoring of the abnormal condition and the protection against failure. Several methods have been used for the detection of failure of journal bearings, one of the main elements of mechanical system. The methods most frequently used are vibration and temperature monitoring, but these are unable to monitor the wear conditions exactly. In this study, an ultrasonic measument method, one of the non-destructive testing methods, was introduced as the monitoring technology. Furtermore a pattem recognition method was applied to analyze the ultrasonic signal. The monitoring system using the pattern recognition method is composed of digital signal processing units and uses Hamming net algorithm for the recognition of ultrasonic waves. From the journal bearing wear test, the occurrence of adhesive wear of the white metal in rubbing contact with the shaft was exactly detected by this system, and the wear status of the journal bearing was monitored by measuring the wear thickness.

• Transactions on Electrical and Electronic Materials
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• 제14권1호
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• pp.20-23
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• 2013

When applying superconducting wire to power machines, an investigation needs to be carried out on the characteristics of wire phase changes in connection with the insulating layer. This study examined trends in the increase of the wire's resistance and the characteristics of its recovery from quenching by a current-applied cycle at temperatures of 90 K, 180 K, and 250 K. The procedure was conducted based on the thickness and presence (or absence) of the insulating wire layers. To achieve this, YBCO thin-film wires with the same critical temperatures were prepared with copper and stainless steel stabilizing layers. At levels (-one, three, and five-), with superior performance, polyimide pressure-sensitive adhesive tape was attached to the wires at a very low temperature. The eight prepared test samples were wound around the linear frames. The wire's voltage and current created from the phase change characteristics were measured at the wire's prescribed temperature, using the four-point probe method. The wire's resistance and recovery characteristics were examined for each cycle at temperatures of 90 K, 180 K, and 250 K.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.292-298
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• 2001

An experimental investigation of the effect of composite patching repair was conducted to characterize the fatigue crack growth behavior in thick A16061-T6 (6mm) panels with single bonded patch by fiber reinforced composite patch. Four patch lengths and no patch plate were examined. An analytical procedure, involving three-dimensional finite element method having three layers to model cracked aluminum plate, epoxy by adhesive and composite patch, is calculated the stress intensity factors. From the calculated stress intensity factors, the fatigue crack growth rates are obtained. At the single patching type, different fatigue crack growth ratios through the plate thickness were investigated by using the experimental and analytical results. The results demonstrated that there was a definite variation in fatigue life depending on the size of composite patch. While crack reached the patch end, retardation of crack growth was also revealed in the bonded repair.

• 한국가구학회지
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• 제19권5호
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• pp.319-327
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• 2008

As art of lamination by plywood got to be generally used, it became a suitable material for expressing live curves that were not able to be expressed on wood furniture made of plank and timber, as well as, openwork deep in curved space, heavy quality of material, and changing contour line-looking wave lines with different process angles. As an alternative, it would be good to build a full scale model, since it would provide practice in form-building and it would also provide a chance to correct the form. Less material can be used and reduce the cutting process by Properly trimming models made of soft formal structure such as Styrofoam Iso-pink and adhesive Styrofoam, and separating the layers and using them on shape cutting of plywood with the same thickness. And by attaching the model veneer that was used in shape cutting of the model and using it as a cutting guide, we can reduce the error of work and successively build the planned form. Since this study is about the need of a full scale model for a laminated wood model and an efficient process, this study concentrates more on process.

• Journal of Welding and Joining
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• 제21권5호
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• pp.555-560
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• 2003

In automobile industry, it is necessary to reduce the weight from the view point of energy and environmental problems in these days. One of the ways for weight reduction is using adhesive aluminum structures. In this study, ultrasonic signals reflected from the adhesively bonded joint layer are used to evaluate the adhesively bonded joints. FFT is performed to determine bond-layer parameters such as effective thickness and frequency for adhesively bonded joint Al 6061 plates in comparison with the measured and theoretical ratios. And the parameters of ultrasonic wave and the J-integral are investigated to evaluate the adhesively bonded joint strength by DCB specimens.

• Steel and Composite Structures
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• 제23권2호
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• pp.161-172
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• 2017

A new composite tube connection method called the pre-tightened teeth connection technique is proposed to improve the composite tube connection efficiency. This paper first introduces the manufacturing process of the proposed technique. It then outlines how the mechanical properties of this technology were tested using four test groups. The factors that influence the load-bearing capacity and damage model of the connection were analyzed, and finally, the transfer load mechanism was investigated. The following conclusions can be obtained from the research results. (1) The new technique improves the compressive connection efficiency by a maximum of 79%, with the efficiency exceeding that of adhesive connections of the same thickness. (2) Changing the depth of teeth results in two types of damage: local compressive damage and shear damage. The bearing capacity can be improved by increasing the depth, length, and number of teeth as well as the pre-tightening force. (3) The capacity of the technique to transfer high loads is a result of both the relatively high interlaminar shear strength of the pultruded composite and the interlaminar shear strength increase provided by the pre-tightening force. The proposed technique shows favorable mechanical properties, and therefore, it can be extensively applied in the engineering field.

• 보존과학회지
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• 제24권
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• pp.43-56
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• 2008

현재 철제유물 강화처리 시 사용하는 아크릴계 수지인 Parabid NAD10은 용제로 VM&P Naphtha만을 사용하고 있다. 그러나 이를 사용하여 강화처리 할 경우 코팅 후의 광택이 높아 전시 및 관람에 불편함을 준다는 문제가 제기되고 있다. 이러한 단점 보완을 위해 대체 용제로 YK-VMP를 선정하여 각 용제별 코팅 특성을 비교 분석하였다. 표면관찰, 박막 두께, 접착력, 접촉각 및 표면에너지, 광택도, 황변실험, EIS 평가 등의 일련의 분석을 통해 용제별 코팅 특성을 비교한 결과, 기존의 VM&P Naphtha를 대신하여 YK-VMP를 사용하여도 강화처리 효과에는 큰 영향을 주지 않으면서도 광택을 더 낮춰주는 효과가 나타나는 것을 확인하였다.