The Experts below are selected from a list of 8166 Experts worldwide ranked by ideXlab platform

G. H. Yoon - One of the best experts on this subject based on the ideXlab platform.

  • topology optimization for stationary fluid structure interaction problems using a new monolithic formulation
    International Journal for Numerical Methods in Engineering, 2010
    Co-Authors: G. H. Yoon
    Abstract:

    This paper outlines a new procedure for topology optimization in the steady-state fluid–structure interaction (FSI) problem. A review of current topology optimization methods highlights the difficulties in alternating between the two distinct sets of governing equations for fluid and structure dynamics (hereafter, the fluid and structural equations, respectively) and in imposing coupling boundary conditions between the separated fluid and solid domains. To overcome these difficulties, we propose an alternative monolithic procedure employing a unified domain rather than separated domains, which is not computationally efficient. In the proposed analysis procedure, the spatial differential operator of the fluid and structural equations for a Deformed Configuration is transformed into that for an unDeformed Configuration with the help of the deformation gradient tensor. For the coupling boundary conditions, the divergence of the pressure and the Darcy damping force are inserted into the solid and fluid equations, respectively. The proposed method is validated in several benchmark analysis problems. Topology optimization in the FSI problem is then made possible by interpolating Young's modulus, the fluid pressure of the modified solid equation, and the inverse permeability from the damping force with respect to the design variables. Copyright © 2009 John Wiley & Sons, Ltd.

  • topology optimization for stationary fluid structure interaction problems using a new monolithic formulation
    International Journal for Numerical Methods in Engineering, 2010
    Co-Authors: G. H. Yoon
    Abstract:

    This paper outlines a new procedure for topology optimization in the steady-state fluid-structure interaction (FSI) problem. A review of current topology optimization methods highlights the difficulties in alternating between the two distinct sets of governing equations for fluid and structure dynamics (hereafter, the fluid and structural equations, respectively) and in imposing coupling boundary conditions between the separated fluid and solid domains. To overcome these difficulties, we propose an alternative monolithic procedure employing a unified domain rather than separated domains, which is not computationally efficient. In the proposed analysis procedure, the spatial differential operator of the fluid and structural equations for a Deformed Configuration is transformed into that for an unDeformed Configuration with the help of the deformation gradient tensor. For the coupling boundary conditions, the divergence of the pressure and the Darcy damping force are inserted into the solid and fluid equations, respectively. The proposed method is validated in several benchmark analysis problems. Topology optimization in the FSI problem is then made possible by interpolating Young's modulus, the fluid pressure of the modified solid equation, and the inverse permeability from the damping force with respect to the design variables.

Matti Ristinmaa - One of the best experts on this subject based on the ideXlab platform.

  • topology optimization utilizing inverse motion based form finding
    Computer Methods in Applied Mechanics and Engineering, 2015
    Co-Authors: Mathias Wallin, Matti Ristinmaa
    Abstract:

    Topology optimization at finite strain setting using the concept of inverse motion based form finding is introduced. This novel procedure allows boundary conditions and shape of the structure in the operating, Deformed, state to be prescribed. The outcome of the optimization algorithm will be the shape of the unDeformed structure, i.e. the state in which the structure should be manufactured. The objective of the optimization considered is to find the stiffest structure for a given amount of material. The problem is regularized using a Helmholtz filter which is formulated in the Deformed Configuration. Both the elastic boundary value problem and the partial differential equation associated with the Helmholtz filter are solved using the finite element method. The optimization problem is solved using a sequence of convex separable approximations. The paper is closed by 2D as well as 3D numerical examples that clearly illustrates that the method is able to find optimal solutions for inverse motion finite strain topology optimization problems.

  • inverse motion based form finding for quasi incompressible finite electroelasticity
    International Journal for Numerical Methods in Engineering, 2013
    Co-Authors: Anna Ask, Ralf Denzer, Andreas Menzel, Matti Ristinmaa
    Abstract:

    This work deals with inverse-motion-based form finding for electroelasticity. The inverse motion problem is formulated for the electroelastic case, and the resulting equations are implemented within a finite element framework. A four-field variational approach is adopted, taking into consideration the typically incompressible behavior of the elastomer materials commonly used in electromechanical applications. By means of numerical simulations, the inverse-motion-based form finding makes it possible to design the referential Configuration so that a given set of loads and boundary conditions results in a prespecified Deformed Configuration. The computational finite element framework established in this work allows for such numerical simulations and testing and thereby the possibility to improve the design and accuracy in electroelastic applications such as grippers, sensors, and seals. (Less)

Pierre Villon - One of the best experts on this subject based on the ideXlab platform.

  • optimal design and optimal control of structures undergoing finite rotations and elastic deformations
    arXiv: Neural and Evolutionary Computing, 2009
    Co-Authors: Adnan Ibrahimbegovic, Catherine Knopflenoir, Anna Kucerova, Pierre Villon
    Abstract:

    In this work we deal with the optimal design and optimal control of structures undergoing large rotations. In other words, we show how to find the corresponding initial Configuration and the corresponding set of multiple load parameters in order to recover a desired Deformed Configuration or some desirable features of the Deformed Configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non-standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures.

  • optimal design and optimal control of structures undergoing finite rotations and elastic deformations
    International Journal for Numerical Methods in Engineering, 2004
    Co-Authors: Adnan Ibrahimbegovic, Catherine Knopflenoir, Anna Kucerova, Pierre Villon
    Abstract:

    In this work, we deal with the optimal design and optimal control of structures undergoing large rotations and large elastic deformations. In other words, we show how to find the corresponding initial Configuration through optimal design or the corresponding set of multiple load parameters through optimal control, in order to recover a desired Deformed Configuration or some desirable features of the Deformed Configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non-standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures.

Adnan Ibrahimbegovic - One of the best experts on this subject based on the ideXlab platform.

  • optimal design and optimal control of structures undergoing finite rotations and elastic deformations
    arXiv: Neural and Evolutionary Computing, 2009
    Co-Authors: Adnan Ibrahimbegovic, Catherine Knopflenoir, Anna Kucerova, Pierre Villon
    Abstract:

    In this work we deal with the optimal design and optimal control of structures undergoing large rotations. In other words, we show how to find the corresponding initial Configuration and the corresponding set of multiple load parameters in order to recover a desired Deformed Configuration or some desirable features of the Deformed Configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non-standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures.

  • optimal design and optimal control of structures undergoing finite rotations and elastic deformations
    International Journal for Numerical Methods in Engineering, 2004
    Co-Authors: Adnan Ibrahimbegovic, Catherine Knopflenoir, Anna Kucerova, Pierre Villon
    Abstract:

    In this work, we deal with the optimal design and optimal control of structures undergoing large rotations and large elastic deformations. In other words, we show how to find the corresponding initial Configuration through optimal design or the corresponding set of multiple load parameters through optimal control, in order to recover a desired Deformed Configuration or some desirable features of the Deformed Configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non-standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures.

Mathias Wallin - One of the best experts on this subject based on the ideXlab platform.

  • topology optimization utilizing inverse motion based form finding
    Computer Methods in Applied Mechanics and Engineering, 2015
    Co-Authors: Mathias Wallin, Matti Ristinmaa
    Abstract:

    Topology optimization at finite strain setting using the concept of inverse motion based form finding is introduced. This novel procedure allows boundary conditions and shape of the structure in the operating, Deformed, state to be prescribed. The outcome of the optimization algorithm will be the shape of the unDeformed structure, i.e. the state in which the structure should be manufactured. The objective of the optimization considered is to find the stiffest structure for a given amount of material. The problem is regularized using a Helmholtz filter which is formulated in the Deformed Configuration. Both the elastic boundary value problem and the partial differential equation associated with the Helmholtz filter are solved using the finite element method. The optimization problem is solved using a sequence of convex separable approximations. The paper is closed by 2D as well as 3D numerical examples that clearly illustrates that the method is able to find optimal solutions for inverse motion finite strain topology optimization problems.