Rouhollah Tavakoli

Thermal Optimization of the Continuous Casting Process using Distributed Parameter Identification Approach — Controlling the Curvature of Solid-Liquid Interface

  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering, Multidisciplinary Design Optimization, Optimization of Systems modeled by PDEs

    Thermal optimization of vertical continuous casting process is considered in the present study. The goal is to find the optimal distribution of temperature and interfacial heat transfer coefficients corresponding to the primary and secondary cooling systems, in addition to the pulling speed, such that the solidification along the main axis of strand approaches to the … Read more

    Optimal design of multiphase composites under elastodynamic loading

  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering, Civil and Environmental Engineering, Mechanical Engineering

    An algorithm is proposed to optimize the performance of multiphase structures (composites) under elastodynamic loading conditions. The goal is to determine the distribution of material in the structure such that the time-averaged total stored energy of structure is minimized. A penalization strategy is suggested to avoid the checkerboard instability, simultaneously to generate near 0-1 topologies. … Read more

    Unconditionally energy stable time stepping scheme for Cahn-Morral equation: application to multi-component spinodal decomposition and optimal space tiling

  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering, Basic Sciences Applications, Optimization of Systems modeled by PDEs Tags , , , , , ,

    An unconditionally energy stable time stepping scheme is introduced to solve Cahn-Morral-like equations in the present study. It is constructed based on the combination of David Eyre’s time stepping scheme and Schur complement approach. Although the presented method is general and independent to the choice of homogeneous free energy density function term, logarithmic and polynomial … Read more

    Computationally Efficient Approach for the Minimization of Volume Constrained Vector-Valued Ginzburg-Landau Energy Functional

  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering

    The minimization of volume constrained vector-valued Ginzburg-Landau energy functional is considered in the present study. It has many applications in computational science and engineering, like the conservative phase separation in multiphase systems (such as the spinodal decomposition), phase coarsening in multiphase systems, color image segmentation and optimal space partitioning. A computationally efficient algorithm is presented … Read more

    Multimaterial topology optimization by volume constrained Allen-Cahn system and regularized projected steepest descent method

  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering, Mechanical Engineering, Multidisciplinary Design Optimization

    A new computational algorithm is introduced in the present study to solve multimaterial topology optimization problems. It is based on the penalization of the objective functional by the multiphase volume constrained Cahn-Hilliard energy functional. The update procedure is based on the gradient flow of the objective functional by a fractional step projected steepest descent method. … Read more

    On the Coupled Continuous Knapsack Problems: Projection Onto the Volume Constrained Gibbs N-Simplex

  • Rouhollah Tavakoli
    • Categories Applications - OR and Management Sciences, Convex Optimization Tags , , ,

    Coupled continuous quadratic knapsack problems (CCK) are introduced in the present study. The solution of a CCK problem is equivalent to the projection of an arbitrary point onto the volume constrained Gibbs N-simplex, which has a wide range of applications in computational science and engineering. Three algorithms have been developed in the present study to … Read more

    Alternating active-phase algorithm for multimaterial topology optimization problems — a 115-line MATLAB implementation

  • Mohammad Mohsenie
  • Rouhollah Tavakoli
    • Categories Applications - Science and Engineering

    A new algorithm for the solution of multimaterial topology optimization problems is introduced in the present study. The presented method is based on the splitting of a multiphase topology optimization problem into a series of binary phase topology optimization sub-problems which are solved partially, in a sequential manner, using a traditional binary phase topology optimization … Read more

    Note: Optimal non-homogeneous composites for dynamic loading revisited

  • Rouhollah Tavakoli
    • Categories Mechanical Engineering Tags , , ,

    The continuous adjoint sensitivity analysis for a class of optimal design problem, formerly studied in (Turteltaub, 2005), is revisited in this note. Full details of derivation is presented. It is shown that the adjoint PDE derived in this study is not identical to one derived in (Turteltaub, 2005). Article Download View Note: Optimal non-homogeneous composites … Read more

    Quest for the control on the second order derivatives: topology optimization with functional includes the state’s curvature

  • Rouhollah Tavakoli
    • Categories Distributed Control, Multidisciplinary Design Optimization, Optimization of Systems modeled by PDEs Tags , , , ,

    Many physical phenomena, governed by partial differential equations (PDEs), are second order in nature. This makes sense to pose the control on the second order derivatives of the field solution, in addition to zero and first order ones, to consistently control the underlaying process. However, this type of control is nontrivial and to the best … Read more

    Minimum weight Topology optimization subject to unsteady heat equation and space-time pointwise constraints — toward automatic optimal riser design in the shape casting process

  • Rouhollah Tavakoli
    • Categories Distributed Control, Mechanical Engineering, Multidisciplinary Design Optimization Tags , , , , ,

    The automatic optimal design of feeding system in the shape casting process is considered in the present work. In fact, the goal is to find the optimal position, size, shape and topology of risers in the shape casting process. This problem is formulated as a minimum weight topology optimization problem subjected to a nonlinear transient … Read more