• KIEAE Journal
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• 제9권2호
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• pp.53-58
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• 2009

There are increasing developments and uses of functional building materials are recently developed and introduced to the test method for the materials. Especially, moisture problem has a major role are also being established in indoor air quality problems. The purpose of this study is to evaluate the water vapour adsorption/desorption property of a ceiling material. The variation of the temperature and moisture were measured with the application materials by mock up test based on JIS 1470-1. The result shows that water vapour adsorption/desorption property of ceiling material is appeared in changes of moisture adsorption and desorption in comparison with that of a general ceiling material. Therefore, in case of decreasing and increasing in humidity, these materials can be used as an finishing material to sustain comfort condition.

• 한국도로학회논문집
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• 제16권5호
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.74-79
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• 2010

Automotive industries are interested in material development with low weight and recycling. Grommet is made from EPDM at rubber and used as an automotive component. The nonlinear material properties of rubber are important to predict the behaviors of rubber product. This study concerns material property test to achieve stress-strain curve. Curve fitting is carried out to obtain the nonlinear material constant. The nonlinear material constants of rubber are used for the nonlinear finite element analysis. The results of finite element analysis is executed to predict the behavior property of grommet.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.59-62
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• 2001

Flow induced vibration in steam generators has caused dynamic interactions between tubes and contacting materials resulting in fretting wear . Series of experiments have been performed to examine the wear properties of Inconel 690 steam generator tubes in various environmental conditions. For the present study, the test rig was designed to examine the fretting wear and rolling wear properties in high temperature(room temperature - 290。C) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of the steam generator tube materials. To investigate the wear mechanism of material, the worn was observed using scanning electron microscopy. The weight loss increase at higher test temperature was caused by the decrease of water viscosity and the mechanical property change of tube material. The mechanical property changes of steam generator tube material, such as decrease of hardness or yield stress in the high temperature tests. From the SEM observation of worn surfaces, the severe wear scars were observed in specimens tested at the higher temperature.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.311-318
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• 2000

In constructions of dams and ports structure, gravels are used as principle structural materials. Gravels have different material property compared with other materials like soil and concretes, etc. For example, material properties of gravels obtained from normal triaxial compression test are usually overestimated due to scale and penetration effects. Also, material properties of gravels under dynamic loads are the main interest when structural behavior of rockfill dam under earthquake loads is analyzed. The development of large triaxial compression apparatus is needed for the better estimation of material property of gravel. This paper reports work in progress to development of large triaxial compression apparatus.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.546-552
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• 2012

This paper is a study on squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material. For this, data of pressure and temperature dependent material properties of lining is achieved by using lining data base and exponential curve fit. Complex eigenvalue analysis is performed for predicting squeal noise frequency and instability and chassis dynamo test is performed for achieving squeal noise frequency, sound pressure level, occurrence temperature & pressure. Initial multi models are composed for considering complex interface conditions such as pad ear-clip, piston-housing and guide pin-torque member. The simulation result of base models is compared with the test result. Squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material is performed and analyzed using multi models. And additional condition is disc material property variation. Entire simulation conditions are combined and analyzed. Finally, this paper proposes direction of the warm squeal noise model.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.295-298
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• 2005

This paper is concerned with the precision material property measurement of a micro metal thin foil that is used in MEMS technology. Since these MEMS components require great precision and accuracy, evaluation of reliability such as the lift cycle endurance test, impact test, and residual stress test is necessary for these components. However, in practice, real reliability tests are not easy to perform due to consideration of various factors. Rather than actual testing, it would be much easier to evaluate the reliability of components by the analytical approach. Although the analytical method is utilized by software tools, it is obviously necessary to acquire fundamental properties of materials through real test methods. In this paper, the oriented mechanical properties of aluminum thin foil are measured by nano scale material property measurement system.

• 한국정밀공학회지
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• 제3권3호
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• pp.13-21
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• 1986

Turning property of metal is affected by the cutting condition, tool geome- try and cutting material. But the turning property of welded material is not welknown. Welded structures usually contain nonhomogeneity, defects and resi- dual stresses due to differential contraction between welded metal and base metal. In this paper, authors conducted the experimental test on the turning property, by changing turning condition and welding electrodes of the welded specimens. The results obtained in these experimental tests are as follows; (1) Within the limit of this experimental test, the cutting force of the weld zone is bigger than that of base metal, and this phenomena is caused by the different mechanical property of the weld zone. The range of the variation of cutting force in the weld zone is caused by the nonhomogeneity of the weld zone, respectively. (2) The surface roughness follows the general characteristic of the effect of cutting condition on the surface roughness and the surface roughness of the weld zone shows coarse surface comparing with that of the base metal. (3) The specimen welded by the electrode E4301, shows worse cutting property than that of E4361 and E4313.

• Computers and Concrete
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• 제9권4호
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• pp.293-310
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• 2012

This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1229-1242
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• 2005

When natural rubber is used for a long period of time, it becomes aged; it usually becomes hardened and loses its damping capability. This aging process affects not only the material property but also the (fatigue) life of natural rubber. In this paper the aging effects on the material property and the fatigue life were experimentally investigated. In addition, several fatigue life prediction equations for natural rubber were proposed. In order to investigate the aging effects on the material property, the load-stretch ratio curves were plotted from the results of the tensile test, the compression test and the simple shear test for virgin and heat-aged rubber specimens. Rubber specimens were heat-aged in an oven at a temperature ranging from $50^{\circ}C$ to $90^{\circ}C$ for a period ranging from 2 days to 16 days. In order to investigate the aging effects on the fatigue life, fatigue tests were conducted for differently heat-aged hourglass-shaped and simple shear specimens. Moreover, finite element simulations were conducted for the specimens to calculate physical quantities occurring in the specimens such as the maximum value of the effective stress, the strain energy density, the first invariant of the Cauchy-Green deformation tensor and the maximum principal nominal strain. Then, four fatigue life prediction equations based on one of the physical quantities could be obtained by fitting the equations to the test data. Finally, the fatigue life of a rubber bush used in an automobile was predicted by using the prediction equations, and it was compared with the test data of the bush to evaluate the reliability of those equations.