• 제목/요약/키워드: anisotropic equations

검색결과 132건 처리시간 0.019초

유한요소법에 의한 비등방성 두꺼운 원통형 쉘 및 얇은 원통형 쉘의 비교 해석 (A Comparative Analysis of Anisotropic Thick Cylindrical Shells and Anisotropic Thin Cylindrical Shells by Finite Element Method)

  • 김기동;박원태
    • 복합신소재구조학회 논문집
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    • 제1권3호
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    • pp.17-23
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    • 2010
  • 본 연구는 비등방성 원통형 쉘의 휨문제에 대한 해석 기법을 제시하였다. 비등방성 원통형 쉘의 지배방정식을 해석하기 위해 유한요소법을 사용하였다. 두꺼운 쉘이론과 얇은 쉘이론을 사용하여 쉘의 폭-두께비 및 여러 가지 경계조건을 갖는 비등방성 원통형 쉘에 대한 해석결과를 비교 분석하였다. 본 연구의 수치해석 결과는 비등방성 원통형 쉘의 휨 거동 분석에 기여할 것으로 보인다.

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탄소성 구성 방정식을 이용한 삼차원 브레이드 복합재료의 역학적 해석 (Mechanical Analysis of 3D Circular Braided Glass Fiber Reinforced Composites Using Elastic-Plastic Constitutive Equations)

  • 류한선;이명규;김지훈;정관수
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2004년도 추계학술발표대회 논문집
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    • pp.147-150
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    • 2004
  • In order to describe the mechanical behavior of highly anisotropic and asymmetric materials such as fiber­reinforced composites, the elastic-plastic constitutive equations were used here based on the recently developed yield criterion and hardening laws. As for the yield criterion, modified Drucker-Prager yield surface was used to represent the orthotropic and asymetric properties of composite materials, while the anisotropic evolution of back­stress was accounted for the hardening behavior. Experimental procedures to obtain the material parameters of the hardening laws and yield surface are presented for 3D Circular Braided Glass Fiber Reinforced Composites. For verification purpose, comparisons of finite element simulations using the elastic-plastic constitutive equations, anisotropic elastic constitutive equations and experiments were performed for the three point bending tests. The results of finite element simulations showed good agreements with experiments, especially for the elastic-plastic constitutive equations with yield criterion considering anisotropy as well as asymmetry and anisotropic back stress evolution rule.

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Anisotropic-Asymmetric Yield Criterion and Anisotropic Hardening Law for Composite Materials: Theory and Formulations

  • Kim Ji-Hoon;Lee Myoung-Gyu;Chung Kwan-Soo;Youn Jae-Ryoun;Kang Tae-Jin
    • Fibers and Polymers
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    • 제7권1호
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    • pp.42-50
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    • 2006
  • In this paper, elasto-plastic constitutive equations for highly anisotropic and asymmetric materials are developed and their numerical implementation is presented. Some engineering materials such as fiber reinforced composites show different material behavior in the different material directions (anisotropy) as well as in tension and compression (asymmetry). Although these materials have mostly been analyzed using the anisotropic elastic constitutive equations, the necessity of consideration of plastic properties has been frequently reported in the previous works. In order to include both the anisotropic and asymmetric properties of composite materials, the Drucker-Prager yield criterion is modified by adding anisotropic parameters and initial components of translation. The implementation procedure for the developed theory and algorithms is presented based on the implicit finite element scheme. The measured data from the previous work are used to validate the present constitutive equations.

비등방성 얇은 쉘 및 두꺼운 쉘의 해석연구 (A Study on the Analysis of Anisotropic Thin and Thick Shells)

  • 박원태
    • 한국산학기술학회논문지
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    • 제6권6호
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    • pp.525-530
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    • 2005
  • 본 연구에서는 비등방성 두꺼운 셀 및 얇은 쉘의 휨문제에 대한 해석결과를 제시하였다. 복잡한 편미분방정식을 포함하는 쉘의 역학적 문제에 대한 수치해석을 위해 유한요소법을 사용하였으며, 비등방성 셀의 휨문제에 대한 지배방정식은 키르호프 가정에 의한 얇은 쉘이론과 민들린 가정에 의한 두꺼운 쉘이론을 이용하여 유도하였으며, 쉘의 폭 - 두께비에 따른 해석결과를 비교 검토하였으며, 본 연구의 수치해석방법은 비등방성 쉘의 휨거동 분석 및 설계에 사용될 수 있을 것으로 본다.

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비등방성 얇은 곡선보 및 두꺼운 곡선보의 해석연구 (A Study on the Analysis of Anisotropic Curved Thin Beams and Anisotropic Curved Thick Beams)

  • 박원태
    • 한국산학기술학회논문지
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    • 제8권1호
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    • pp.116-120
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    • 2007
  • 본 연구에서는 비등방성 두꺼운 곡선보와 얇은 곡선보의 휨문제에 대한 해석결과를 제시하였다. 비등방성 재료는 재료의 성질이 각 방향으로 다르기 때문에 거동이 복잡하여 해석해를 구하기가 어렵다. 따라서 비등방성 두꺼운 보의 미분방정식의 해를 구하기 위해 본 연구에서는 수치해석법인 유한요소법이 사용되었으며, 비등방성 두꺼운 곡선보와 얇은 곡선보의 휨문제에 대한 해석을 위해 두꺼운 보이론과 얇은 보이론이 사용되며, 비등방성 두꺼운 곡선보와 얇은 곡선보의 휨문제에 대한 해석결과를 비교 검토하였다.

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On the theory of curved anisotropic plate

  • Chiang, Yih-Cherng
    • Structural Engineering and Mechanics
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    • 제22권6호
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    • pp.741-759
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    • 2006
  • A general theory which describes the elastic response of a curved anisotropic plate subjected to stretching and bending will be developed by considering the nonlinear effect that reflecting the non-flat geometry of the structure. By applying a newly derived $6{\times}6$ matrix constitutive relation between force resultants, moment resultants, mid-plane strains and deformed curvatures, the governing differential equations for a curved anisotropic plate is developed in the usual manner, namely, by consideration of the constitutive relation and equilibrium equations. Solutions are obtained for simply-supported boundary conditions and compared to corresponding solutions that neglecting the nonlinear effect in the analysis. The comparisons indicate that the nonlinear terms in the equations that caused by the curvature of the structure is crucial for the curved plate analysis. Under certain curved plate geometries the unreasonable results will be induced by neglecting the nonlinear effect in the analysis.

Existence Results for an Nonlinear Variable Exponents Anisotropic Elliptic Problems

  • Mokhtar Naceri
    • Kyungpook Mathematical Journal
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    • 제64권2호
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    • pp.271-286
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    • 2024
  • In this paper, we prove the existence of distributional solutions in the anisotropic Sobolev space $\mathring{W}^{1,\overrightarrow{p}(\cdot)}(\Omega)$ with variable exponents and zero boundary, for a class of variable exponents anisotropic nonlinear elliptic equations having a compound nonlinearity $G(x, u)=\sum_{i=1}^{N}(\left|f\right|+\left|u\right|)^{p_i(x)-1}$ on the right-hand side, such that f is in the variable exponents anisotropic Lebesgue space $L^{\vec{p}({\cdot})}(\Omega)$, where $\vec{p}({\cdot})=(p_1({\cdot}),{\ldots},p_N({\cdot})){\in}(C(\bar{\Omega},]1,+{\infty}[))^N$.

AN EXISTENCE OF THREE DIFFERENT NON-TRIVIAL SOLUTIONS FOR DISCRETE ANISOTROPIC EQUATIONS WITH TWO REAL PARAMETERS

  • Ahmed A.H., Alkhalidi;Haiffa Muhsan B., Alrikabi;Mujtaba Zuhair, Ali
    • Nonlinear Functional Analysis and Applications
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    • 제27권4호
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    • pp.855-867
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    • 2022
  • This study finds three different solutions (3-Sol's) for the fourth order nonlinear discrete anisotropic equations (DAE) with real parameter. We use the variational method(VM) and 𝜙p-Laplacian operator (𝜙p-LO) to prove the main results. In the following paper, we take the parameters λ, 𝜇 such that λ > 0 and 𝜇 ≥ 0 into consideration.

축변환 구성방정식을 이용한 암석 이방성 탄성계수 산정

  • 김영수;이재호;허노영;박영화;최정호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 가을 학술발표회 논문집
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    • pp.729-736
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    • 2000
  • For nonhomogeneous and anisotropic rocks such as schist, shale, etc, a method to determine the anisotropic elastic constants was proposed. Many authors have investigated in detail the behavior elastic constants of anisotropy rocks(Pinto 1970, Amadei 1983, 1992, Amadei & Savage 1989). They concluded that equations of elastic constants E$_1$, E$_2$ and G$_2$ can be derived from the measured strains in arbitrary three directions. And, modulus of elasticity varies according to the inclination of discontinuity in specimens. If we attach three strain gages in accordance with the directions of anisotropy on the rock specimen under uni-axial compression and diametral compression tests, anisotropy elastic constants can be determined by these equations. With this method, the degree of anisotropy will be easily evaluated by simple laboratory test. This paper presents the results of elastic constants due to the angle of bedding planes of anisotropic rock, such as shale, in uni-axial compression and diametral compression tests

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