• Title/Summary/Keyword: elasticity coefficient

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A Study on the Strength and Stiffness of Multi-Stage Cubic Truss Unit Structures (복합 입체형 정육면체 트러스 단위구조체의 강도 및 강성에 대한 해석 연구)

  • Choi, Jeongho
    • Journal of the Korea Convergence Society
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    • v.10 no.4
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    • pp.139-145
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    • 2019
  • This paper investigated the strength and stiffness of composite truss unit structures. The model used is a core-filled model combining the Kagome model and the cube truss model. The material properties used for the analysis are 304 stainless steel with elastic modulus of 193 GPa and yield stress of 215 MPa. The theoretical equation is derived from the relative elasticity relation of Gibson - Ashby ratio, the analysis was performed using Deform 3D, a commercial tool. In conclusion, the relative elasticity for this unit model correlates with 1.25 times the relative density and constant coefficient, elasticity is inversely proportional to pore size. The relative compressive strength has a correlation with relative density of 1.25 times. Proof of this is a real experiment, the derived theoretical relationship should further consider mechanical behavior such as bending and buckling. In the future, it is hoped that the research on the elasticity and the stress according to the structure of the three-dimensional space will be continued.

Measurement of Mechanical and Physical Properties of Pepper for Particle Behavior Analysis

  • Nam, Ju-Seok;Byun, Jun-Hee;Kim, Tae-Hyeong;Kim, Myoung-Ho;Kim, Dae-Cheol
    • Journal of Biosystems Engineering
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    • v.43 no.3
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    • pp.173-184
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    • 2018
  • Purpose: This study was conducted to investigate the mechanical and physical properties of a Korean red pepper variety for particle behavior analysis. Methods: Poisson's ratio, modulus of elasticity, shear modulus, density, coefficient of restitution, and coefficient of friction were derived for "AR Legend," which is a domestic pepper variety. The modulus of elasticity and Poisson's ratio were measured through a compression test using a texture analyzer. The shear modulus was calculated from the modulus of elasticity and Poisson's ratio. The density was measured using a water pycnometer method. The coefficient of restitution was measured using a collision test, and the static and dynamic friction coefficients were measured using a inclined plane test. Each test was repeated 3-5 times except for density measurement, and the results were analyzed using mean values. Results: Poisson's ratios for the pepper fruit and pepper stem were 0.295 and 0.291, respectively. Elastic moduli of the pepper fruit and pepper stem were $1.152{\times}10^7Pa$ and $3.295{\times}10^7Pa$, respectively, and the shear moduli of the pepper fruit and pepper stem were $4.624{\times}10^6Pa$ and $1.276{\times}10^7Pa$, respectively. The density of the pepper fruit and the pepper stem were $601.8kg/m^3$ and $980.4kg/m^3$, respectively. The restitution coefficients between pepper fruits, pepper stems, a pepper fruit and a pepper stem, a pepper fruit and plastic, and a pepper stem and plastic were 0.383, 0.218, 0.277, 0.399, and 0.148, respectively. The coefficients of static friction between pepper fruits, pepper stems, a pepper fruit and a pepper stem, a pepper fruit and plastic, and a pepper stem and plastic were 0.455, 0.332, 0.306, 0.364, and 0.404, respectively. The coefficients of dynamic friction between a pepper fruit and plastic and a pepper stem and plastic were 0.043 and 0.034, respectively.

A New Method for Estimating the Coefficient of Consolidation in Various Stress Conditions (다양한 응력조건을 고려한 새로운 압밀계수 평가방법)

  • Kwak Chan-Mun;Jung Young-Hoon;Kim Chang-Youb;Chung Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.25-32
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    • 2005
  • The coefficient of consolidation has been evaluated using the conventional oedometer tests based on the one-dimensional consolidation theory. In the field, however, the actual response of the soil will be subject to the three-dimensional condition during consolidation. In this research, a new method f3r estimating the coefficient of consolidation for various stress-deformation conditions was proposed. The good agreement between the computed dissipation of pore pressure and the measured data confirms the usefulness and the applicability of the proposed method to predict the exact rate of consolidation.

Characteristic of Elastic Paving Materials in Bicycle Road using Polyurethane (폴리우레탄을 이용한 자전거도로의 탄성포장재 특성)

  • Lee, Young-Sei
    • Journal of the Korean Society of Industry Convergence
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    • v.17 no.1
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    • pp.7-14
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    • 2014
  • In this study, characteristic of elastic paving materials in bicycle road using polyurethane were studied experimentally. As a results, following their good result was obtained. Bicycle road packaging materials are flexural strength g test, ratio of mass change after freezing and thawing, repulsion elasticity test, water Permeation coefficient test and slip resistance test results showed good performance.

Stresses in FGM pressure tubes under non-uniform temperature distribution

  • Eraslan, Ahmet N.
    • Structural Engineering and Mechanics
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    • v.26 no.4
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    • pp.393-408
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    • 2007
  • The effects of material nonhomogeneity and nonisothermal conditions on the stress response of pressurized tubes are assessed by virtue of a computational model. The modulus of elasticity, the Poisson's ratio, the yield strength, and the coefficient of thermal expansion, are assumed to vary nonlinearly in the tube. A logarithmic temperature distribution within the tube is proposed. Under these conditions, it is shown that the stress states and the magnitudes of response variables are affected significantly by both the material nonhomogeneity and the existence of the radial temperature gradient.

An Experimental study on the Viscoelastic Coefficient of Polystyrene (폴리스티렌의 점탄성 계수에 관한 실험적 연구)

  • Yoon, Kyung-Hwan;Yu, Bong-Kun
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.751-754
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    • 2000
  • Stress relaxation experiments were performed to obtain the material properties to be used in the linear viscoelastic study. Master curve of the modulus of polystyrene were obtained by using the time-temperature superposition principle. Because Shyu and Tobolsky's tensile relaxation modulus master curve or Polystyrene material showed very large difference, in-house data were required to calculate the residual stresses in injection-molded products more accurately. Our own experimental data showed that the master curve Shyu's data should be shifted about two orders in material time coordinate.

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OPTIMAL CONSUMPTION AND SLUTSKY EQUATION WITH EPSTEIN-ZIN TYPE PREFERENCE

  • Ahn, Se-Ryoong;Koo, Hyeng-Keun
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.16 no.2
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    • pp.107-124
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    • 2012
  • In this paper we conduct comparative statics for optimal consumption and portfolio selection of an agent who has a utility function of Epstein and Zin type. We derive the Slutsky equations and decompose the total effects of changes into the substitution effects and the income effects. We identify the role of the elasticity of intertemporal substitution and the coefficient of relative risk aversion.

Physical Properties of Recycled Sidewalk Pavement Using Wood Chip (Wood Chip을 사용한 자원순환형 보도 포장체의 물성에 관한 연구)

  • Yu, Hyeok-Jin;Choi, Jae-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.2
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    • pp.91-96
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    • 2010
  • The purpose of this study is to find problems about pedestrian road of tourist resort and to make new type of sidewalk pavement with wood chip and binder using urethane resin on the parks and tourist resort. The wood chip pavement has new economics and durability with comfortable texture. Samples of these pavement materials were tested for tensile strength, permeability and ball rebound value. Also, after immersion for 24 hours, tensile strength, samples' thickness and weight were measured and discussed the strength reduction according to the water immersion. Tensile strength experimentation was examined on dry condition and water immersion. The result of examination on dry condition was 1.06MPa and on water immersion was 0.67MPa. The results showed 36.8% decreasing rate of tensile strength. Permeability experiment test based on field permeability method of pavement were conducted as a result, permeability coefficients were in the range of 0.67~0.78mm/s that all exceeds object permeability coefficient. Elasticity experiment was based on elasticity test method of Japan road association. GB coefficient was 21% and SB coefficient was 10%. GB coefficient and SB coefficient increased if fine aggregate were increased.

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Short Term Interest Rate Model Using Box-Cox Transformation

  • Choi, Young-Soo;Lee, Yoon-Dong
    • Communications for Statistical Applications and Methods
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    • v.14 no.1
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    • pp.241-254
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    • 2007
  • This paper propose a new short-term interest rate model having a different nonlinear drift function and the same diffusion coefficient with Chan et al. (1992) model. The fractional polynomial power of the drift function in our model is linked to the local volatility elasticity of the diffusion coefficient. While the nonlinear drift function estimated by $A\"{\i}t$-Sahalia (1996a) and others has a feature that higher interest rates tend to revert downward and low rates upward, the drift function estimated by our nonlinear model shows that higher interest rate mean-reverts strongly, but, medium rates has almost zero drift and low rates has a very small drift. This characteristic coincides the empirical result based on the nonparametric methodology by Stanton (1997) and the implication by the scatter plot of the short rate data.

Experimental studies on the material properties of high-strength bolt connection at elevated temperatures

  • Li, Guo-Qiang;Yin, Ying-Zhi;Li, Ming-Fei
    • Steel and Composite Structures
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    • v.2 no.4
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    • pp.247-258
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    • 2002
  • The high-temperature material properties of steel are very important to the fire resistance analysis of high-strength bolt connections. This paper reports on the results of the experimental studies on the high-temperature properties of 20 MnTiB steel which is widely used in high-strength bolts, and the friction coefficient of 16Mn steel plates at elevated temperature which is a necessary parameter for bolted frictional connection analysis. The test data includes yield strength, limit strength, modulus of elasticity, elongation and expansion coefficient of 20MnTiB steel at elevated temperature, and the friction coefficients between two 16Mn steel plates under elevated temperatures and after cooling. Based on the data from the tests, the mathematical models for predicting the mechanical properties of 20MnTiB steel and friction coefficients of 16Mn steel plates have been established.