• Title/Summary/Keyword: Material properties

Search Result 18,016, Processing Time 0.044 seconds

A Study on the Material Properties and Durabilities of Epoxy-Type Repairing Materials (에폭시계 보수재료의 재료특성 및 내구성능 분석)

  • 김도겸;이장화;박승범
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1997.10a
    • /
    • pp.659-664
    • /
    • 1997
  • RC structures can deteriorate for many defective factors. In the repair and retrofit works of concrete, epoxy resins are widely used as repair materials. The object of this study is to investigate the material properties and durabilities of epoxy resins which are commonly used in repairing concrete. The material properties such as line-expansion modulus, viscosity, microstructure and physical parameter as well as the durabilities such as gravity change, tensile strength, elongation change were carried out.

  • PDF

Calculation of Material Properties with JMatPro for the Process Simulation (JMatPro를 이용한 공정해석에서의 물성계산)

  • Lee, Kyung-Hoon;Kang, Gyeong-Pil
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.142-145
    • /
    • 2008
  • Process simulation requires accurate and reliable data for a wide variety of material properties, ranging from thermal conductivity to flow stress curves. Traditionally such data are gathered from experimental sources, which has significant disadvantages in that not all of the required data is readily available, it may be from various sources that are themselves inconsistent, measurement of high temperature properties is expensive, and furthermore the properties can be sensitive to microstructure as well as to alloy composition. This article describes the development of a new multi-platform software program called JMatPro, which is based on CALPHAD methodology, for calculating the properties and behavior of multi-component alloys. A feature of the JMatPro is that the calculations are based on sound physical principles rather than purely statistical methods. Thus, many of the shortcomings of methods such as regression analysis can be overcome.

  • PDF

Modal characteristics of partially perforated rectangular plate with triangular penetration pattern

  • Jhung, Myung J.;Jeong, Kyeong H.
    • Structural Engineering and Mechanics
    • /
    • v.55 no.3
    • /
    • pp.583-603
    • /
    • 2015
  • There are so many applications of perforated pates with various penetration patterns. If they are penetrated regularly, it can be represented by solid plate with equivalent material properties, which has a benefit of finite element modelling and reducing computation time for the analysis. Because the equivalent material properties suggested already are not proper to be applicable for the dynamic analysis, it is necessary to extract the equivalent material properties for the dynamic analysis. Therefore, in this study, the equivalent modulus of elasticity are obtained for the perforated plate with a triangular penetration pattern by comparing the natural frequencies of the perforated plate with those of solid plate, which are represented with respect to the ligament efficacy. Using the equivalent material properties suggested, the modal analyses of the partially perforated rectangular plate with a triangular penetration pattern are performed and its applicability is shown by comparing natural frequencies of perforated and homogeneous solid plates from finite element method and analytical method.

Physical and electrical properties of a-C:H deposited by RF-PECVD (RF-PECVD에 의해 증착된 a-C:H 박막의 물리적 및 전기적 특성 분석)

  • 김인준;김용탁;최원석;윤대호;홍병유
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.07a
    • /
    • pp.296-300
    • /
    • 2002
  • Thin films of Hydrogenated amorphous carbon(a-C:H) are generally exhibited by high electrical resistivities from 10$^2$ to 10$\^$16/ Ω$.$cm, resulting in an interesting material for high power, high temperature MIS devices applications. The hydrogenated amorphous carbon(a-C:H) films were deposited on silicon and glass using an rf plasma enhanced CVD method. The resultant film properties were evaluated in the respect of material based on r.f. power variation. The hydrogenated amorphous carbon(a-C:H) films of thickness ranging from 30 to 50 m were deposited at the pressure of 1 ton with the mixture of methane and hydrogen. We have used rf-IR( courier transform IR) and AFM(Atomic force microscopy) for determining physical properties and current-voltage(I-V) measurement for electrical Properties.

  • PDF

Derivation of Equivalent Material Properties of Induction Motor Windings Based on Homogenization Method (균질화기법에 기초한 유도전동기 권선 다발의 등가물성 유도)

  • Bae Jing-Do;Ko Woo-Sik;Cho Jin-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.29 no.4 s.235
    • /
    • pp.518-525
    • /
    • 2005
  • The electromagnetic noise generates when natural frequencies of a stator core with wingdings and frame coincide with or approach natural frequencies of the magnetic motive force. In order to suppress such noise, the estimation of natural frequencies of the motor is important at the design stage. However, the natural frequency analysis is not so easy because motor stator is in the laminated plate structure and windings are composed of wires, insulation sheets and vanishs. Thus the accurate prediction of the equivalent material properties of windings becomes an essential task. In this paper, we derive the equivalent material properties using homogenization methods.

Bending Waves Propagating in a Bar with Periodically Nonuniform Material Properties (재질이 주기적으로 불균일한 보에서 전파하는 굽힘 탄성파)

  • Kim, Jin-O;Mun, Byeong-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.24 no.8 s.179
    • /
    • pp.1923-1930
    • /
    • 2000
  • A bar with periodically nonuniform material properties is selected as a one-dimensional model of a flat-panel speaker. This paper describes a theoretical approach to the bending waves propagating i n the nonuniform bar. The phase speed of the wave is obtained using perturbation techniques for small amplitude, sinusoidal modulation of the flexural rigidity and mass density. It is shown that the wave speed is decreased due to the nonuniformity of the material properties by the amount proportional to the square of the modulation amplitude. The resonance occurring when the wavelength is half of the period of the material properties is analyzed by the method of multiple scales. It is also shown that the wave speed at the resonance mode is decreased by the amount proportional to the modulation amplitude but the wave of this mode does not propagate far enough due to attenuation.

Measurement of Material Properties of Composites for High Temperature using Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서를 이용한 고온용 복합재의 물성 측정)

  • 강동훈;박상욱;김수현;김천곤;홍창선
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2003.04a
    • /
    • pp.31-36
    • /
    • 2003
  • Recently, composite materials are widely used for nozzle, pressure vessel, skins of satellite and many structures under condition of high temperature due to good thermal characteristics such as low CTE, heat-resistance, etc. Fiber optic sensors, especially FBG(fiber Bragg grating) sensors, can be a good counterproposal of strain gages for the measurement of material properties of composites under high temperature. In this research, T700/Epoxy specimens with embedded FBG sensors were fabricated and tested at the Instron with thermal chamber from room temperature to $400^{\circ}C$. The effects of embedding optical fiber on material properties were also verified. And, the experimental results were discussed and analyzed by microphotographs of the composite specimen.

  • PDF

Effective Material Properties of Composite Materials by Using a Numerical Homogenization Approach (균질화 접근법을 통한 복합재의 유효물성치 계산)

  • Anto, Anik Das;Cho, Hee Keun
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.18 no.12
    • /
    • pp.28-37
    • /
    • 2019
  • Due to their flexible tailoring qualities, composites have become fascinating materials for structural engineers. While the research area of fiber-reinforced composite materials was previously limited to synthetic materials, natural fibers have recently become the primary research focus as the best alternative to artificial fibers. The natural fibers are eco-friendly and relatively cheaper than synthetic fibers. The main concern of current research into natural fiber-reinforced composites is the prediction and enhancement of the effective material properties. In the present work, finite element analysis is used with a numerical homogenization approach to determine the effective material properties of jute fiber-reinforced epoxy composites with various volume fractions of fiber. The finite element analysis results for the jute fiber-reinforced epoxy composite are then compared with several well-known analytical models.

Changes on the Abrasion and Mechanical Properties of Warp Knitted Fabric for Footwear with Softeners and Heat Treatments (유연제 및 열처리에 따른 신발용 경편성물의 마모 및 역학 특성 변화)

  • Jeon, Youn-Hee;Koo, Ja-Gil;Jeong, Won-Young;An, Seung-Kook
    • Fashion & Textile Research Journal
    • /
    • v.12 no.4
    • /
    • pp.494-499
    • /
    • 2010
  • Knitted fabrics are very popular for their numerous advantages such as greater comfort, attractive garment appearance, better fit on the body, etc. In this study, we investigated the mechanical properties and abrasion property of warp knitted fabrics for footwear which treated with several softeners to improve abrasion resistance. The antistatic softener among the various softeners showed high improvement in abrasion resistance. Among the mechanical properties with treating conditions, WT (tensile energy), G (shear stiffness), B (bending rigidity) increased as treating timeincreased. But the other mechanical properties were little changed with treating concentration.

On the material properties of shell plate formed by line heating

  • Lim, Hyung Kyun;Lee, Joo-Sung
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.9 no.1
    • /
    • pp.66-76
    • /
    • 2017
  • This paper is concerned with investigating the plastic material properties of steel plate formed by line heating method, and is aimed at implementing more rational design considering the accidental limit states such as collision or grounding. For the present study, line heating test for marine grade steel plate has been carried out with varying plate thickness and heating speed, and then microscopic examination and tensile test have been carried out. From the microscopic, it is found that the grain refined zones like ferrite and pearlite are formed all around the heat affected zone. From the tensile test results, it is seen that yield strength, tensile strength, fracture strain, hardening exponent and strength coefficient vary with plate thickness and heat input quantity. The formulae relating the material properties and heat input parameter should be, therefore, derived for the design purpose considering the accidental impact loading. This paper ends with describing the extension of the present study.