• Title/Summary/Keyword: an orthotropic material

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A Study on Nonlinear Analysis of Reinforced Concrete Structures (철근(鐵筋)콘크리트 구조물(構造物)의 비선형(非線型) 해석(解析)에 관한 연구(硏究))

  • Chang, Dong Il;Kwak, Kae Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.7 no.2
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    • pp.69-77
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    • 1987
  • A finite element method has been developed to study the material nonlinear analysis of reinforced concrte structures. Concrete behavior under the biaxial state of stress is represented by a nonlinear constitutive relationship which incorporates tensile cracking, tensile stiffening effect between cracks and the strain-softening phenomenon beyond the maximum compressive strength. The concrete model used is based upon nonlinear elasticity by assuming concrete to be an orthotropic material and modeled as equivalent uniaxial stress-strain constitutive relationship using equivalent uniaxial strain. The streel reinforcement is assumed to be in a uniaxial stress state and is modeled as a bilinear, elasto-plastic material with strain hardening approximating the Bauschinger effect. In plane stress state, R.C. beams is modeled as a quadratic element that has two degrees of freedom in each node. And this results of finite element analysis are compared with the experimential results of midspan deflection, stresses and strains.

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Derivation of Effective Material Properties of Reinforced Braid Layer Using Detailed 3-D Finite Element Model (상세 유한요소 모델을 이용한 섬유 보강사의 등가물성 유도)

  • Song, Jeong-In;Cho, Jin-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1752-1759
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    • 2004
  • Reinforced braid layer (RBL) in automobile power steering hose plays an important role in power steering system. When the working oil is applied to the power steering hose, RBL suppresses rubber hose deformation from internal pressure and heat expansion. RBL is woven textile composites having a double-row structure of nylon cords twisted with the specific helix angle. In this paper, effective material properties of RBL are estimated using a detailed 3-D finite element model considering its complicated geometry. Numerical experiments based on a superposition method are carried out to simulate uniaxial tensile loading condition.

Non-linear Dynamic Analysis of Reinforced Concrete Slabs Subjected to Explosive Loading Using an Orthotropic Concrete Constitutive Model (이등방성 콘크리트 모델을 이용한 폭발하중을 받는 철근콘크리트 슬래브의 비선형 동적해석)

  • Lee, MinJoo;Kwak, Hyo-Gyoung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.409-416
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    • 2019
  • An improved numerical model for non-linear analysis of reinforced concrete (RC) slabs subjected to blast loading is proposed. This approach considers a strain rate dependent orthotropic constitutive model that directly determines the stress state using the stress-strain relation acquired from the data obtained using the biaxial strength envelope. Moreover, the bond-slip between concrete and reinforcing steel is gradually enlarged after the occurrence of cracks and is concentrated in the plastic hinge region. The bond-slip model is introduced to consider the crack direction of the concrete under a biaxial stress state. Correlation studies between the numerical analysis and the experimental results were performed to evaluate the analytical model. The results show that the proposed model can effectively be used in dynamic analyses of reinforced concrete slab members subjected to explosive loading. Moreover, it was determined that it is important to consider biaxial behavior in the material model and the bond-slip effect.

Analysis of cracks emanating from a circular hole in an orthotropic infinite plate (直交 異方性 無限平版 內部의 圓孔周圍 龜裂 解析)

  • 정성균;홍창선
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.6
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    • pp.895-903
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    • 1987
  • This paper investigates the problem of cracks emanating from a circular hole in an orthotropic infinite plate. The mixed-mode stress intensity factors are obtained by using the modified mapping-collocation method. To investigate the effect of anisotropy and circular hole boundary on crack tip singularity, stress intensity factors are considered as functions of the normalized crack length for various types of laminated composite. The results indicate a strong dependence of the stress intensity factor on the material anisotropy and geometry.

Shear band Formation in an Elasto-Plastic Orthotropic Material Under Plane Stress Deformation (평면 응력상태에서 이등방성탄-소성 재료의 전단띠 형성)

  • 임세영
    • The Korean Journal of Rheology
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    • v.7 no.2
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    • pp.128-138
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    • 1995
  • 본 논문에서는 전단띠형성에 있어서 전단변형의 집중화 현상을 이방성 탄소성 재료 에 대해서 해석하였고 소성스핀과 비등방성이 전단띠 형성에 미치는 영향을 연구하였다. 평 면응력 상태에서 소성스핀을 갖고있는 이방성 탄-소성 재료에 대해서 재료 분랑ㄴ정 해서 을 수행하여 변형률 집중화의 시작에 미치는 소성스핀과 비등방성의 효과를 연구하였다. 해 석 결과 이방성 재료에서의 전단띠 형성은 압축 또는 인장의 하중 형태나 이방성 축의 초기 각도 그리고 소성스핀의크기에 따라 그 시작이 촉진되거나 지연되었고 전단띠 생성의 방향 도 달라졌다.

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Anisotropic Constitutive Model at Large Viscoplastic Deformations (탄소성 대변형에 관한 비등방 구성방정식)

  • Cho, Han-Wook
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1995.10a
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    • pp.178-184
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    • 1995
  • A new combined isotropic/kinematic and orthotropic hardening viscoplastic model is proposed which can account for not only differential orientations but also preferred orientations of grains in n metal at finite plastic deformations with an introduction of multiple spin (rate of rotation) concept within the general framework of the model, the effects of anisotropy and constitutive spins will be discussed in conjunction with a closed-form solution for simple shear in n rigid-plastic material, which will be used to simulate experimental data of Montheillet, et al. (1984) for fixed-end tortion tests at finite plastic deformations.

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A Study on Calculation of Composites Lamina Material Properties through Reverse Engineering of Light Weight Composite Car-body (경량 복합재 차체 구조의 역설계를 통한 복합재료 라미나 물성 산출 기법 연구)

  • Moon, Jin Bum;Kim, Jihoon;Jang, Hong Kyu;Park, Jisang
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.1
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    • pp.1-10
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    • 2017
  • In reverse engineering, one of the main tasks is reconstructing the mechanical properties of used materials. For an isotropic material, it could be defined by a single tensile test using a coupon extracted from the structure. In contrast, CFRP composites require many tests and complex procedures to define all the material properties because CFRP is an orthotropic material and a stacked laminate. In this paper, the procedure to reconstruct composite material properties is studied by using the classical lamination theory and the test data of three different laminates from a composite structure. A sample reconstruction of composite material properties using a composite car body is introduced to verify the method.

A Study on Squeal Noise Simulation considering the Friction Material Property Changes according to Temperature and Pressure in an Automotive Brake Corner Module (차량용 브레이크 코너 모듈에서 마찰재의 온도와 압력에 따른 물성치 변화를 고려한 스퀼 소음 해석 연구)

  • Cho, Hojoon;Kim, Jeong-Tae;Chae, Ho-Joong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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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.

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A Efficient Vibration Analysis Method for the Cooncrete-Steel Deck Slab (콘크리트와 강제데크의 합성 바닥판의 실용적인 진동해석 방법)

  • Kim, Gee-Cheol
    • Journal of Korean Association for Spatial Structures
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    • v.5 no.4 s.18
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    • pp.91-100
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    • 2005
  • Composite slab structures consisted with steel deck plate and concrete material show generally anisotropic structural behavior because of different stiffness between the major direction and sub-direction of deck plate, and also the structures can be regarded as the laminated slab structures. It is necessary for the composite deck slab structures to carry out the exact vibration analysis to evaluate the serviceability. Also, it is needed to evaluate the exact structural behavior of composite deck slab with a layered orthotropic materials. In this paper, the thickness of topping concrete and deck plate are used to calculate the material coefficient stiffness of a sub-direction, and an equivalent depth calculated from sectional stiffness of concrete and deck plate is applied to get the stiffness of a major direction. The stiffness of two layered composite plates with different depth is determined by laminated theory. It is concluded that the presented method can efficiently analyze the structural behavior of composite deck slab consisted with steel deck plate and concrete material in the practical engineering field.

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Material Property Characterization Method and Experimental Measurement of the Effective Thermal Conductivities of Woven Fabric Composite Materials (직물 복합재료의 물성치 특성화 기법 및 실험적 계측)

  • Moon, Young-Kyu;Goo, Nam-Seo;Kim, Cheol;Woo, Kyung-Sik
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.64-69
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    • 2001
  • In general, laminate effective orthotropic thermal conductivities are dependent on fiber and matrix material properties, fiber volume fraction and fabric geometric parameters. This paper deals with the predicting method of the transverse and the in-plane thermal conductivities of plain weave fabric composites based on the three dimensional series-parallel thermal resistance network. Thermal resistance network was applied to unit cell model that characterizes the periodically repeated pattern of plain weave. Also, an experiment apparatus is setup to measure the thermal conductivities of composite material. The numerical and experimental results of carbon/epoxy plain weave are compared.

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