• Title/Summary/Keyword: mixed variational formulation

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MIXED QUASI VARIATIONAL INEQUALITIES INVOLVING FOUR NONLINEAR OPERATORS

  • Pervez, Amjad;Khan, Awais Gul;Noor, Muhammad Aslam;Noor, Khalida Inayat
    • Honam Mathematical Journal
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    • v.42 no.1
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    • pp.17-35
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    • 2020
  • In this paper we introduce and consider a new class of variational inequalities with four operators. This class is called the extended general mixed quasi variational inequality. We show that the extended general mixed quasi variational inequality is equivalent to the fixed point problem. We use this alternative equivalent formulation to discuss the existence of a solution of extended general mixed quasi variational inequality and also develop several iterative methods for solving extended general mixed quasi variational inequality and its variant forms. We consider the convergence analysis of the proposed iterative methods under appropriate conditions. We also introduce a new class of resolvent equation, which is called the extended general implicit resolvent equation and establish an equivalent relation between the extended general implicit resolvent equation and the extended general mixed quasi variational inequality. Some special cases are also discussed.

GENERALIZED SET-VALUED MIXED NONLINEAR QUASI VARLIATIONAL INEQUALITIES

  • H, M-U
    • Journal of applied mathematics & informatics
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    • v.5 no.1
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    • pp.73-90
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    • 1998
  • In this paper we introduce and study a number of new classes of quasi variational inequalities. using essentially the projection technique and its variant forms we prove that the gen-eralized set-valued mixed quasivariational inequalities are equivalent to the fixed point problem and the Wiener-Hopf equations(normal maps). This equivalence enables us to suggest a number of iterative algorithms solving the generalized variational inequalities. As a special case of the generalized set-valued mixed quasi variational in-equalities we obtain a class of quasi variational inequalities studied by Siddiqi Husain and Kazmi [35] but there are several inaccuracies in their formulation of the problem the statement and the proofs of the problem the statement and the proofs of their results. We have removed these inaccuracies. The correct formulation of thir results can be obtained as special cases from our main results.

A Mixed Variational Principle of Fully Anisotropic Linear Elasticity (이방성탄성문제의 혼합형변분원리)

  • 홍순조
    • Computational Structural Engineering
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    • v.4 no.2
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    • pp.87-94
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    • 1991
  • In this paper, a mixed variational principle applicable to the linear elasticity of inhomogeneous anisotropic materials is presented. For derivation of the general variational principle, a systematic procedure for the variational formulation of linear coupled boundary value problems developed by Sandhu et al. is employed. Consistency condition of the field operators with the boundary operators results in explicit inclusion of boundary conditions in the governing functional. Extensions of admissible state function spaces and specialization to a certain relation in the general governing functional lead to the desired mixed variational principle. In the physical sense, the present variational principle is analogous to the Reissner's recent formulation obtained by applying Lagrange multiplier technique followed by partial Legendre transform to the classical minimum potential energy principle. However, the present one is more advantageous for the application to the general anisotropic materials since Reissner's principle contains an implicit function which is not easily converted to an explicit form.

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CONVERGENCE ANALYSIS OF PARALLEL S-ITERATION PROCESS FOR A SYSTEM OF VARIATIONAL INEQUALITIES USING ALTERING POINTS

  • JUNG, CHAHN YONG;KUMAR, SATYENDRA;KANG, SHIN MIN
    • Journal of applied mathematics & informatics
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    • v.36 no.5_6
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    • pp.381-396
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    • 2018
  • In this paper we have considered a system of mixed generalized variational inequality problems defined on two different domains in a Hilbert space. It has been shown that the solution of a system of mixed generalized variational inequality problems is equivalent to altering point formulation of some mappings. A new parallel S-iteration type process has been considered which converges strongly to the solution of a system of mixed generalized variational inequality problems.

Transverse stress determination of composite plates

  • Phoenix, S.S.;Sharma, M.;Satsangi, S.K.
    • Structural Engineering and Mechanics
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    • v.27 no.4
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    • pp.457-475
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    • 2007
  • Analysis of transverse stresses at layer interfaces in a composite laminate has always been a challenging task. Composite structures possess highly irregular material properties at layer interfaces, which cause high shear stresses. Classical Plate Theory and First Order Shear Deformation Theory (FSDT) use post computing to calculate transverse stresses. This paper presents Reissner Mixed Variational Theorem (RMVT) based finite element model to carry out layer-wise analysis of composite laminates. Selective integration scheme has been used. The formulation has been validated by solving numerical examples and comparing the results with those published in the literature.

A Variational Numerical Method of Linear Elasticity through the Extended Framework of Hamilton's Principle (확장 해밀턴 이론에 근거한 선형탄성시스템의 변분동적수치해석법)

  • Kim, Jinkyu
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.1
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    • pp.37-43
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    • 2014
  • The extended framework of Hamilton's principle provides a new rigorous weak variational formalism for a broad range of initial boundary value problems in mathematical physics and mechanics in terms of mixed formulation. Based upon such framework, a new variational numerical method of linear elasticity is provided for the classical single-degree-of-freedom dynamical systems. For the undamped system, the algorithm is symplectic with respect to the time step. For the damped system, it is shown to be accurate with good convergence characteristics.

Numerical nonlinear bending analysis of FG-GPLRC plates with arbitrary shape including cutout

  • Reza, Ansari;Ramtin, Hassani;Yousef, Gholami;Hessam, Rouhi
    • Structural Engineering and Mechanics
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    • v.85 no.2
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    • pp.147-161
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    • 2023
  • Based on the ideas of variational differential quadrature (VDQ) and finite element method (FEM), a numerical approach named as VDQFEM is applied herein to study the large deformations of plate-type structures under static loading with arbitrary shape hole made of functionally graded graphene platelet-reinforced composite (FG-GPLRC) in the context of higher-order shear deformation theory (HSDT). The material properties of composite are approximated based upon the modified Halpin-Tsai model and rule of mixture. Furthermore, various FG distribution patterns are considered along the thickness direction of plate for GPLs. Using novel vector/matrix relations, the governing equations are derived through a variational approach. The matricized formulation can be efficiently employed in the coding process of numerical methods. In VDQFEM, the space domain of structure is first transformed into a number of finite elements. Then, the VDQ discretization technique is implemented within each element. As the last step, the assemblage procedure is performed to derive the set of governing equations which is solved via the pseudo arc-length continuation algorithm. Also, since HSDT is used herein, the mixed formulation approach is proposed to accommodate the continuity of first-order derivatives on the common boundaries of elements. Rectangular and circular plates under various boundary conditions with circular/rectangular/elliptical cutout are selected to generate the numerical results. In the numerical examples, the effects of geometrical properties and reinforcement with GPL on the nonlinear maximum deflection-transverse load amplitude curve are studied.

A new incompatible mixed formulation for incompressible and nearly-incompressible media (비압축성 문제에 대한 비적합 복합유한요소 정식화)

  • Ju, Sang-Baek;Sin, Hyo-Chol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.2
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    • pp.365-371
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    • 1998
  • In the present study, we attempted to add the incompatible functions as additional variable terms to the conventional u-p formulation. It is derived from the four-field generalized variational principle that encompasses velocity, pressure, velocity strains and stress fields as independent interpolated variables. As a severe test of the present formulation, we have investigated the driven cavity with the corner velocity singularity like leaky lid. Through the test, the present element performs very well without unstable oscillation of pressure distribution.

In-Plane Flexural Vibration Analysis of Arches Using Three-Noded Hybrid-Mixed Element (3절점 혼합유한요소를 이용한 아치의 면내굽힘진동해석)

  • Kim, J.G.
    • Journal of Power System Engineering
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    • v.10 no.4
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    • pp.83-89
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    • 2006
  • Curved beams are more efficient in transfer of loads than straight beams because the transfer is effected by bending, shear and membrane action. The finite element method is a versatile method for solving structural mechanics problems and curved beam problems have been solved using this method by many author. In this study, a new three-noded hybrid-mixed curved beam element is proposed to investigate the in-plane flexural vibration behavior of arches depending on the curvature, aspect ratio and boundary conditions, etc. The proposed element including the effect of shear deformation is based on the Hellinger-Reissner variational principle, and employs the quadratic displacement functions and consistent linear stress functions. The stress parameters are then eliminated from the stationary condition of the variational principle so that the standard stiffness equations are obtained. Several numerical examples confirm the accuracy of the proposed finite element and also show the dynamic behavior of arches with various shapes.

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A mixed 8-node hexahedral element based on the Hu-Washizu principle and the field extrapolation technique

  • Chen, Yung-I;Wu, Guan-Yuan
    • Structural Engineering and Mechanics
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    • v.17 no.1
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    • pp.113-140
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    • 2004
  • A mixed eight-node hexahedral element formulated via the Hu-Washizu principle as well as the field extrapolation technique is presented. The mixed element with only three translational degrees of freedom at each node can provide extremely accurate and reliable performance for popular benchmark problems such as spacial beams, plates, shells as well as general three-dimensional elasticity problems. Numerical calculations also show that when extremely skewed and coarse meshes and nearly incompressible materials are used, the proposed mixed element can still possess excellent behaviour. The mixed formulation starts with introduction of a parallelepiped domain associated with the given general eight-node hexahedral element. Then, the assumed strain field at the nodal level is constructed via the Hu-Washizu variational principle for that associated parallelepiped domain. Finally, the assumed strain field at the nodal level of the given hexahedral element is established by using the field extrapolation technique, and then by using the trilinear shape functions the assumed strain field of the whole element domain is obtained. All matrices involved in establishing the element stiffness matrix can be evaluated analytically and expressed explicitly; however, a 24 by 24 matrix has to be inverted to construct the displacement extrapolation matrix. The proposed hexahedral element satisfies the patch test as long as the element with a shape of parallelepiped.