scholarly journals LAGRANGIAN METHOD FOR ALGORITHM OPTIMIZATION OF RIBBED THIN PLATES

2018 ◽  
pp. 140-147
Author(s):  
R. P. Moiseenko ◽  
O. O. Kondratenko
Keyword(s):  
Lagrange Multipliers ◽  
Lagrange Equation ◽  
Thin Plates ◽  
Algorithm Optimization ◽  
Lagrange Equations ◽  
Equation Solution ◽  
Optimum Parameters ◽  
Equation Analysis ◽  
Optimality Properties ◽  
Method Of Lagrange Multipliers

The paper presents two iteration algorithms for the equation solution using the method of Lagrange multipliers. It is shown that these iteration algorithms do not converge. For comparison, we use the optimum parameters of a ribbed plate obtained by other methods. The proposed method is based on the specific properties of optimality of ribbed plates formulated as a result of the Lagrange equation analysis. These optimum parameters satisfy each of Lagrange equations. The solution of these equations shows that optimization of ribbed plates is possible only with the use of specific optimality properties.

scholarly journals A generalization of Lagrange multipliers

1970 ◽  
Vol 3 (3) ◽  
pp. 353-362 ◽  
Author(s):  
B. D. Craven
Keyword(s):  
Banach Spaces ◽  
Lagrange Multipliers ◽  
Lagrange Equation ◽  
Linear Mapping ◽  
Real Field ◽  
Dimensional Problem ◽  
Continuous Linear ◽  
Continuous Linear Mapping ◽  
Finite Dimensional ◽  
Method Of Lagrange Multipliers

The method of Lagrange multipliers for solving a constrained stationary-value problem is generalized to allow the functions to take values in arbitrary Banach spaces (over the real field). The set of Lagrange multipliers in a finite-dimensional problem is shown to be replaced by a continuous linear mapping between the relevant Banach spaces. This theorem is applied to a calculus of variations problem, where the functional whose stationary value is sought and the constraint functional each take values in Banach spaces. Several generalizations of the Euler-Lagrange equation are obtained.

Applying the Method of Lagrange Multipliers to Derive an Estimator for Unsampled Soil Properties

2014 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Set Foong Ng ◽  
Pei Eng Ch’ng ◽  
Yee Ming Chew ◽  
Kok Shien Ng
Keyword(s):  
Soil Properties ◽  
Lagrange Multipliers ◽  
Unbiased Estimator ◽  
Soil Property ◽  
Minimum Variance ◽  
Distance Method ◽  
True Value ◽  
A Site ◽  
Method Of Lagrange Multipliers ◽  
Inverse Distance

Soil properties are very crucial for civil engineers to differentiate one type of soil from another and to predict its mechanical behavior. However, it is not practical to measure soil properties at all the locations at a site. In this paper, an estimator is derived to estimate the unknown values for soil properties from locations where soil samples were not collected. The estimator is obtained by combining the concept of the ‘Inverse Distance Method’ into the technique of ‘Kriging’. The method of Lagrange Multipliers is applied in this paper. It is shown that the estimator derived in this paper is an unbiased estimator. The partiality of the estimator with respect to the true value is zero. Hence, the estimated value will be equal to the true value of the soil property. It is also shown that the variance between the estimator and the soil property is minimised. Hence, the distribution of this unbiased estimator with minimum variance spreads the least from the true value. With this characteristic of minimum variance unbiased estimator, a high accuracy estimation of soil property could be obtained.

The Determination of Maximum Range for an Unpowered Atmospheric Vehicle

1964 ◽  
Vol 68 (638) ◽  
pp. 111-116 ◽  
Author(s):  
D. J. Bell
Keyword(s):  
Calculus Of Variations ◽  
Lagrange Multipliers ◽  
Digital Computer ◽  
Necessary Conditions ◽  
Lagrange Equations ◽  
Initial Portion ◽  
End Conditions ◽  
Maximum Range ◽  
Isothermal Atmosphere

SummaryThe problem of maximising the range of a given unpowered, air-launched vehicle is formed as one of Mayer type in the calculus of variations. Eulers’ necessary conditions for the existence of an extremal are stated together with the natural end conditions. The problem reduces to finding the incidence programme which will give the greatest range.The vehicle is assumed to be an air-to-ground, winged unpowered vehicle flying in an isothermal atmosphere above a flat earth. It is also assumed to be a point mass acted upon by the forces of lift, drag and weight. The acceleration due to gravity is assumed constant.The fundamental constraints of the problem and the Euler-Lagrange equations are programmed for an automatic digital computer. By considering the Lagrange multipliers involved in the problem a method of search is devised based on finding flight paths with maximum range for specified final velocities. It is shown that this method leads to trajectories which are sufficiently close to the “best” trajectory for most practical purposes.It is concluded that such a method is practical and is particularly useful in obtaining the optimum incidence programme during the initial portion of the flight path.

scholarly journals DIRICHLET PROBLEMS FOR THE 1-LAPLACE OPERATOR, INCLUDING THE EIGENVALUE PROBLEM

2007 ◽  
Vol 09 (04) ◽  
pp. 515-543 ◽  
Author(s):  
BERND KAWOHL ◽  
FRIEDEMANN SCHURICHT
Keyword(s):  
Eigenvalue Problem ◽  
Laplace Operator ◽  
Lagrange Equation ◽  
Variational Problems ◽  
Dirichlet Boundary Conditions ◽  
Necessary Condition ◽  
Dirichlet Problems ◽  
Lagrange Equations ◽  
Existence Of Minimizers ◽  
Formal Limit

We consider a number of problems that are associated with the 1-Laplace operator Div (Du/|Du|), the formal limit of the p-Laplace operator for p → 1, by investigating the underlying variational problem. Since corresponding solutions typically belong to BV and not to [Formula: see text], we have to study minimizers of functionals containing the total variation. In particular we look for constrained minimizers subject to a prescribed [Formula: see text]-norm which can be considered as an eigenvalue problem for the 1-Laplace operator. These variational problems are neither smooth nor convex. We discuss the meaning of Dirichlet boundary conditions and prove existence of minimizers. The lack of smoothness, both of the functional to be minimized and the side constraint, requires special care in the derivation of the associated Euler–Lagrange equation as necessary condition for minimizers. Here the degenerate expression Du/|Du| has to be replaced by a suitable vector field [Formula: see text] to give meaning to the highly singular 1-Laplace operator. For minimizers of a large class of problems containing the eigenvalue problem, we obtain the surprising and remarkable fact that in general infinitely many Euler–Lagrange equations have to be satisfied.

On the Nonuniqueness of Solutions Obtained With Simplified Variational Principles

1996 ◽  
Vol 63 (3) ◽  
pp. 820-827 ◽  
Author(s):  
H. Mang ◽  
P. Helnwein ◽  
R. H. Gallagher
Keyword(s):  
Variational Principle ◽  
Lagrange Multipliers ◽  
Variational Principles ◽  
Boundary Value ◽  
Geometrically Nonlinear ◽  
Lagrange Equations ◽  
Geometrically Nonlinear Theory ◽  
Nonuniqueness Of Solutions ◽  
Uniqueness Of The Solution ◽  
Bending Of Beams

The attempt to satisfy subsidiary conditions in boundary value problems without additional independent unknowns in the form of Lagrange multipliers has led to the development of so-called “simplified variational principles.” They are based on using the Euler-Lagrange equations for the Lagrange multipliers to express the multipliers in terms of the original variables. It is shown that the conversion of a variational principle with subsidiary conditions to such a simplified variational principle may lead to the loss of uniqueness of the solution of a boundary value problem. A particularly simple form of the geometrically nonlinear theory of bending of beams is used as the vehicle for this proof. The development given in this paper is entirely analytical. Hence, the deficiencies of the investigated simplified variational principle are fundamental.

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