• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1367-1372
• /
• 2007

Over the past decade, many computational researches have been performed to investigate quantitative relationships between load-displacement and material properties. But piling-up which causes errors to estimate mechanical material properties remains the most significant unresolved issue in nano-indentation test. This study has estimated quantitative aspects of the effects of material properties, especially work hardening exponent, on piling up/sinking in response of various materials. Using FE Analysis, piling up/sinking in response when material is indented by sharp indenter is investigated to evaluate the effects of material properties. From the FE analysis result, quantitative relationships between piling up/sinking in height and material properties is assessed using dimensional analysis which is used to define scaling variables and universal functions. And nano-indentaion test is performed to verify this relation on various materials. From the result of comparison with prediction from dimensional function and experiment, the work hardening exponent was found to have greater influence on the piling up/sinking in height during the nano-indentation than other material properties, such as elastic modulus and yield stress.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.11
• /
• pp.1651-1656
• /
• 2017

This paper deals with the thermal and mechanical properties of ceramic coating material for bus bars. A ceramic coated samples were prepared for the mechanical properties test. There are two types of samples. One is a square shape and the other is a busbar shape. Each sample was deteriorated for 30 days to compare the thermal and mechanical properties with the non-degraded samples. Two thermal properties tests are TGA and flammability tests, and four mechanical properties tests are drop impact test, cross cut, tensile test, and bend test. The ceramic coating material was never damaged by impact and did not separate from aluminum in the cross cut test. In the tensile test, the breakage of the insulating material did not occur until aluminum fractured, and the breakage of the insulating material did not occur until the maximum load in the bending test. The decomposition temperature (melting point) of the ceramic coating material was higher than that of other epoxy insulators. This ceramic coating material is nonflammable and it has excellent fire stability.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.11a
• /
• pp.43-46
• /
• 2006

The Hwangtoh is one of the traditional construction material used in wall, plastering material, and ondol (Korean underfloor heating system) with stone and wood. It is an important greenness material and it has much advantages such as; high storage of heat, auto-purification, antibiotic ability, and emission of far infrared rays. But, it is not developed and not used in modern construction because of its low strength and properties of dry shrinkage crack. According to the recent researches and studies, it is evaluated for natural pozzolanic material like flyash or pozzolan. It's possibility on construction material is high because it's chemical and mineralogical proportion is like as Metakaolin and Kaolinite. In this point of view, this study aims to analyze the physical properties on Hwangtoh mortar through an experiment with various activation condition of Hwangtoh, which is natural pozzolanic material, for the purpose of increase the using possibility in construction material.

• Journal of the Korean Society of Industry Convergence
• /
• v.9 no.4
• /
• pp.309-315
• /
• 2006

Important material properties of UCAS rod can divide by tension characteristic of base rod part and both end part of U type anchor. Tensile properties of base rod part need as concrete reinforcement material as an alternative material of reinforcing rod, and tensile properties of U type anchor is used at connection with UCAS rod. This treatise carry out tensile test of UCAS rod, examine necessary properties such as strength, elastic modulus and maximum capacity of UCAS rod as reinforcement material of concrete. Also, to examine material properties carry out tensile test of U type anchor.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.221-224
• /
• 2003

Polyvinyl chloride (PVC)/gypsum Polymer blend materials were prepared by melt blending of PVC with gypsum and additives. Effect of gypsum content on the properties of PVC/gypsum Polymer blend material was studied by investigating physico-mechanical properties, thermal properties and morphology development. It was found that the replacement of gypsum for methylene-butadiene-sarene (MBS) component in PVC/gypsum polymer blend material enhanced the tensile strength, but gradually decreased its impact strength. Besides, with the increase of gypsum content, the elongation at break of material gradually decreased. The Presence of the different gypsum contents made a shift of g1ass transition temperature and increased the thermal stability as well as the processing temperature range of polymer blends. The observation of morphology, the results of the physico-mechanical properties and thermal properties proved simultaneously that PVC/gypsum Polymer blend material with the gypsum content of 22.56 wt.% reached the optimum results among five kinds of PVC/gypsum Polymer blend materials investigated.

• Journal of the Korean Society for Railway
• /
• v.7 no.2
• /
• pp.142-148
• /
• 2004

When material properties depend much on positions in a material or it is difficult to make test specimens from a material or component, an instrumented indentation test described in ISO 14577-1, 14577-2 or KS B 0950 can be used to measure material properties and damage. In this study, first of all, the principals of the instrumented indentation test, KS B 0950 are introduced and yield strengths, tensile strengths and work hardening exponents of base materials, heat affected zones and weld materials are measured. In addition, the influence of post-weld heat treatment on the material properties is investigated. Finally the fatigue lift of butt welded specimens are evaluated by the local strain approach. To calculate local strains and stresses, elasto-plastic finite element analysis is conducted using the measured properties.

• Fibers and Polymers
• /
• v.6 no.4
• /
• pp.322-331
• /
• 2005

Graduated compression stockings (GCS) have been widely used for the prophylaxis and treatment of venous diseases. Their gradient pressure function largely related to their fabric structure and material properties. By combing fabric physical testing and wear trials, this study investigated the GCSs fabric structure and material properties at different locations along the stocking hoses, and quantitatively analyzed the effects of fabrics on skin pressure longitudinal and transverse distributions. We concluded that, Structural characteristics and material properties of stocking fabrics were not uniform along the hoses, but a gradual variation from ankle to thigh regions, which significantly influenced the corresponding skin pressure gradient distributions; Tensile (WT, EM) and shearing properties (G) generated most significant differences among ankle, knee and thigh regions along the stocking hose, which significantly influenced the skin pressure lognitudinal gradient distribution. More material indices generating significant gradual changes occurred in the fabric wale direction along stocking hose, meaning that materials properties in wale direction would exert more important impact on the skin pressure gradient performances. And, the greater tensibility and smoother surface of fabric in wale direction would contribute to put stocking on and off, and facilitate wearers' leg extension-flexion movements. The indices of WT and EM of stocking fabrics in series A have strong linear correlations with skin pressure lognitudinal distribution, which largely related to their better performances in gradual changes of material properties. Skin pressure applied by fabric with same material properties produced pronounced differences among four different directions around certain cross-sections of human leg, especially at the ankle region; and, the skin pressure magnitudes at ankle region were more easily influenced by the materials properties, which were considered to be largely related to the anatomic structure of human leg.

• Journal of Powder Materials
• /
• v.23 no.1
• /
• pp.8-14
• /
• 2016

A bulk-type Ta material is fabricated using the kinetic spray process and its microstructure and physical properties are investigated. Ta powder with an angular size in the range $9-37{\mu}m$ (purity 99.95%) is sprayed on a Cu plate to form a coating layer. As a result, ~7 mm-sized bulk-type high-density material capable of being used as a sputter material is fabricated. In order to assess the physical properties of the thick coating layer at different locations, the coating material is observed at three different locations (surface, center, and interface). Furthermore, a vacuum heat treatment is applied to the coating material to reduce the variation of physical properties at different locations of the coating material and improve the density. OM, Vickers hardness test, SEM, XRD, and EBSD are implemented for analyzing the microstructure and physical properties. The fabricated Ta coating material produces porosity of 0.11~0.12%, hardness of 311~327 Hv, and minor variations at different locations. In addition, a decrease in the porosity and hardness is observed at different locations upon heat treatment.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.6C
• /
• pp.221-229
• /
• 2011

A core zone of a fill dam is an important part of a dam for cutoff of water. Therefore, the material properties and behavior characteristics of a core zone are very important factors in an analysis of dam stability. However, the investigation on material properties of actual dam core is extremely rare so far. The material properties have been acquired or estimated by indirect methods like a surface wave surveying or empirical equation. In this research, in-situ and laboratory tests were conducted during dismantling an existing dam directly to investigate characteristics of the core zone in terms of the depth and transient variation of properties after construction of the dam. Dynamic material properties like shear wave velocity and shear modulus were measured and compared to other existing empirical correlations. In addition, aging characteristics of dynamic material properties were investigated by a series of laboratory tests.

• Journal of Power System Engineering
• /
• v.4 no.2
• /
• pp.40-45
• /
• 2000

Some engineering materials are often known to have considerable spatial variation in their resisting strength and other properties. The objective of this study is to investigate the averaging effect and the applicability of extremal statistic for the statistical size effect. In the present study, it is assumed that the material property is a stationary random process in space. The theoretical autocorrelation function of the material strength are discussed for several correlation lengths. And, in order to investigate the statistical size effect, the material properties was simulated by using the non-Gaussian random process method. The material properties were plotted on the Weibull probability papers. The main results are summarized as follows: The autocorrelation function of the material properties are almost independent of the averaging length. The variance decreases with increasing the averaging length. As correlation length is smaller, the slope is larger. And also, it was found that Weibull statistics based on the weakest-link model could not explain the spatial variation of material properties with respect to the size effect satisfactory.