Encontrados 6 documentos, a visualizar página 1 de 1
Path-following and augmented Lagrangian methods for contact problems in linear ...
Stadler, GeorgA certain regularization technique for contact problems leads to a family of problems that can be solved efficiently using infinite-dimensional semismooth Newton methods, or in this case equivalently, primal-dual active set strategies. We present two procedures that use a sequence of regularized problems to obtain the solution of the original contact problem: first-order augmented Lagrangian, and path-following...
Frictional contact of an anisotropic piezoelectric plate
Figueiredo, Isabel N.; Stadler, GeorgThe purpose of this paper is to derive and study a new asymptotic model for the equilibrium state of a thin anisotropic piezoelectric plate in frictional contact with a rigid obstacle. In the asymptotic process, the thickness of the piezoelectric plate is driven to zero and the convergence of the unknowns is studied. This leads to two-dimensional Kirchhoff-Love plate equations, in which mechanical displacement ...
Elliptic optimal control problems with L1-control cost and applications for the...
Stadler, GeorgElliptic optimal control problems with L1-control cost are analyzed. Due to the nonsmooth objective functional the optimal controls are identically zero on large parts of the control domain. For applications, in which one cannot put control devices (or actuators) all over the control domain, this provides information about where it is most efficient to put them. We analyze structural properties of L1- control c...
A primal-dual active set algorithm for three-dimensional contact problems with ...
Hüeber, Stefan; Stadler, Georg; Wohlmuth, Barbara I.In this paper, efficient algorithms for contact problems with Tresca and Coulomb friction in three dimensions are presented and analyzed. The numerical approximation is based on mortar methods for nonconforming meshes with dual Lagrange multipliers. Using a nonsmooth complementarity function for the 3D friction conditions, a primal-dual active set algorithm is derived. The method determines active contact and f...
A practical map labeling algorithm utilizing image processing and force-directe...
Stadler, Georg; Steiner, Tibor; Beiglböck, JürgenAutomatic placement of text corresponding to graphical objects is an important issue in several applications such as Geographical Data Systems (GIS), Cartography, and Graph Drawing. While usually only a finite number of possible placements is available, in this paper we allow for an infinite number of placements and only require the label to be as close as possible to its corresponding feature. We focus on real...
Optimal control of piezoelectric anisotropic plates
Figueiredo, Isabel Narra; Stadler, GeorgThis paper is concerned with the application of optimal control techniques to a static piezoelectric anisotropic thin plate model. To take physical limitations into account, the space of electric potential fields is restricted, i.e., control constraints are imposed. After deriving the first-order necessary conditions for the problem, a primal-dual active set strategy for its solution is presented. In a numerica...
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