• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2002.05a
• /
• pp.97-102
• /
• 2002

The ability to pass between bars is one of the most important performance of self-compacting concrete or high-flowability concrete since it determines the final filling capacity which influences the strength and durability of hardened concrete in structure. Therefore it has been evaluated by many researchers using different kinds of testing apparatuses. The assessments of passing ability, however, differ largely according to the style, the dimension and the criteria in apparatuses, and the value obtained from one apparatus cannot be converted those of the others. There needs a rheological approach to the better understanding of the passing behavior of fresh concrete between reinforcing bars, where the flow velocity of concrete becomes slow and the blockade sometimes occurs due to the interference between aggregates and reinforcing bars. Experimental works were conducted to clarity the effects of the clearance between reinforcing bars, the volume of aggregate and the rheological properties of matrix on the behavior from the rheological point view and showed the rational mix proportioning of concrete.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.04a
• /
• pp.119-126
• /
• 2003

In the conventional reinforced-concrete bridge deck, concrete and steels are likely to be deteriorated and corroded under the influence of noxious environment. To cope with these problems caused in the conventional reinforced-concrete bridge deck, pultruded composite bridge deck having light weight, high strength, corrosion resistence and durability is developed. Based on the previous study, Pultruded composite bridge deck is designed. For the DB24 truck load finite element analysis is performed to verify whether it meets both strength and serviceability design criteria. For the fabricated and assembled deck panel, structural testings are conducted. This paper present structural details and field application and testing results of composite bridge deck are presented. of composite bridge deck.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.9 no.2
• /
• pp.35-43
• /
• 1985

The purpose of this study was to analyse the characteristics and the problems of commercial zippers such as polyester coil zippers, plastic zippers and brass zippers by testing their properties. The sizes of the samples used for this were $\sharp$3, $\sharp$5 and $\sharp$8($\sharp$7 only in case of brass zippers), and all of them were selected in the same lot and collected from 4 different domestic companies. Original samples and another samples laundered 1, 3, 5 and 10 times were measured in terms of colorfastness, durability of coating of zipper, longitudinal dimensional change, operability of zipper, strength of zipper chain crosswise, and reciprocating movement of zipper. In conclusion, the properties of the zippers were revealed differently according to their kinds. Therefore, it was recommended that the present test standard should be modified, in order to improve them in quality.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.04a
• /
• pp.441-441
• /
• 2012

Noise and vibration performance plays an important role in the development of rotating components, such as engines, drivelines, transmission systems, compressors and pumps. The presence of torsional vibrations and other specific phenomena require the dynamic behaviour of systems and components to be designed accurately in order to avoid comfort and durability related problems. This paper provides an overview of the instrumentation and challenges related to torsional vibration testing. The accuracy and performance of five measurement techniques (high-speed incremental encoder, dual beam laser interferometer, zebra tape, zebra disc, direct pulse measurements with magnetic probe) is investigated by measurements on a Fiat Punto 1.4 liter engine. The potential sources of error are discussed to explain the inaccuracies of each technique.

• International Journal of Concrete Structures and Materials
• /
• v.18 no.3E
• /
• pp.207-211
• /
• 2006

This paper presents an experimental study on the repair performance of sprayed engineered cementitious composites(ECC) serving as a repair material. Sprayable ECC, which exhibit tensile strain-hardening behavior in the hardened state and maintain sprayable properties in the fresh state, have been developed by using a parallel control of micromechanical design and rheological process design. The effectiveness of sprayable ECC in providing durable repaired structures was assessed by spraying the ECC and testing them for the assessment. The experimental results revealed that, when sprayed ECC were used as a repair material, both load carrying capacity and ductility represented by the deformation capacity at peak load of the repaired flexural beams were obviously increased compared to those of commercial prepackaged mortar(PM) repaired beams. The significant enhancement in the energy absorption capacity and tight crack width control of the ECC repair system treated with wet-mix spraying process suggests that sprayed ECC can be effective in extending the service life of rehabilitated infrastructures.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.4 s.97
• /
• pp.95-101
• /
• 1999

In this paper, we propose a dynamic model of an escalator which can be used to build a design database. The model permits to estimate the forces applied to the structure by calculating three primary types of forces; the torque required to operate the escalator, the reaction forces at part interconnection points, and contact forces between parts. These forces can then be used to calculate dynamic stresses in the structure which is required to estimate the durability of the structure. Result of the computer model are compared with testing results. This simulation model is used to construct a design database. So when we design a new escalator, this design database can be used to make a new simulation model which makes it possible for us to do a Knowledge-Based-Design.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.962-965
• /
• 2002

Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, Hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The operation software for simultaneously controlled multi-axial simulator is developed and the input and output data are displayed window based PC controller in real time. The software to generate the real road profile are developed. This paper developed a road profile reappearance software and simultaneously apply 3-axial actuator to white noise, so we verified the propriety of reappearance software through accomplishes an real test.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1993.10a
• /
• pp.97-102
• /
• 1993

The application of epxy composite materials for the outdoor insulating systems has some significant advan-tages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The paper describes the results of high voltage investigations carried out different aging types of epoxy resin insulator and silicone grease coating. The insulators have been exposed 3000 hours to weather-o-meter and 12 months to outdoor. In this connection, the main study of paper is form the basis of develop-ment of principal technologies of epoxy composites which ard: (1)manufacturing of insulator, (2)high vol-tage testing under dry and wet condition, (3)mechani-cal properties, (4)accelerated weather-ometer test and outdoor exposed, artificial polution.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.2
• /
• pp.140-147
• /
• 2003

Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the link unit which is able to realize the 3 element forces such as vertical force, lateral force, and longitudinal force that are applied to the road simulator is designed. Also, the designed link is verified with kinematics and inverse-kinematics. From this results, the designed factor satisfied the maximum stroke so that it satisfied the requirements for 3-axial road simulator.

• Journal of the Korean institute of surface engineering
• /
• v.36 no.3
• /
• pp.272-283
• /
• 2003

Mild steel and zinc specimens were tested in five atmospheric testing sites of Vietnam in order to collect the corrosion databank as well as to study the corrosion mechanism in tropical conditions, in period of 1997-2000. The results obtained showed that the corrosion rate of steel is in the range of $10-50\;{\mu}m/year$ and of zinc is of $1-5\;{\mu}m/year$. They are interpretable in the comparison with the data obtained in different countries in the South East Asian as well as previous reports of Vietnamese nation project In atmospheric corrosion. The main factors affecting the corrosion in Vietnam tropical conditions are TOW (time of wetness) and salinity. The relationship between sulfur dioxide and corrosion of metals, particularly, zinc was not found clearly. An explanation was suggested about the complex effect of different pieces present in tropical atmosphere and about the alternative of the dominant factors such as humidity, salinity or temperature.