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Applied Mechanics Commons

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Full-Text Articles in Applied Mechanics

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza Sep 2010

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …


The Bending Strip Method For Isogeometric Analysis Of Kirchhoff–Love Shell Structures Comprised Of Multiple Patches, J. Kiendel, Y. Bazilevs, Ming-Chen Hsu, R. Wuchner, K. U. Bletzigner Aug 2010

The Bending Strip Method For Isogeometric Analysis Of Kirchhoff–Love Shell Structures Comprised Of Multiple Patches, J. Kiendel, Y. Bazilevs, Ming-Chen Hsu, R. Wuchner, K. U. Bletzigner

Ming-Chen Hsu

In this paper we present an isogeometric formulation for rotation-free thin shell analysis of structures comprised of multiple patches. The structural patches are C1- or higher-order continuous in the interior, and are joined with C0-continuity. The Kirchhoff–Love shell theory that relies on higher-order continuity of the basis functions is employed in the patch interior as presented in Kiendl et al. [36]. For the treatment of patch boundaries, a method is developed in which strips of fictitious material with unidirectional bending stiffness and zero membrane stiffness are added at patch interfaces. The direction of bending stiffness is chosen to be transverse …


Improving Stability Of Stabilized And Multiscale Formulations In Flow Simulations At Small Time Steps, Ming-Chen Hsu, Y. Bazilevs, V. M. Calo, T. E. Tezduyar, T.J.R. Hughes Feb 2010

Improving Stability Of Stabilized And Multiscale Formulations In Flow Simulations At Small Time Steps, Ming-Chen Hsu, Y. Bazilevs, V. M. Calo, T. E. Tezduyar, T.J.R. Hughes

Ming-Chen Hsu

The objective of this paper is to show that use of the element-vector-based definition of stabilization parameters, introduced in [T.E. Tezduyar, Computation of moving boundaries and interfaces and stabilization parameters, Int. J. Numer. Methods Fluids 43 (2003) 555–575; T.E. Tezduyar, Y. Osawa, Finite element stabilization parameters computed from element matrices and vectors, Comput. Methods Appl. Mech. Engrg. 190 (2000) 411–430], circumvents the well-known instability associated with conventional stabilized formulations at small time steps. We describe formulations for linear advection–diffusion and incompressible Navier–Stokes equations and test them on three benchmark problems: advection of an L-shaped discontinuity, laminar flow in a square …