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The present paper reports about numerical simulations and model experiments concerned with the fluid flow in the continuous casting process of steel. This work was carried out in the LIMMCAST project in the framework of the Helmholtz alliance LIMTECH. A brief description of the LIMMCAST facilities used for the experimental modeling at HZDR is given here. Ultrasonic and inductive techniques and the X-ray radioscopy were employed for flow measurements or visualizations of two-phase flow regimes occurring in the submerged entry nozzle and the mold. Corresponding numerical simulations were performed at TUBAF taking into account the dimensions and properties of the model experiments. Numerical models were successfully validated using the experimental data base. The reasonable and in many cases excellent agreement of numerical with experimental data allows to extrapolate the models to real casting configurations. Exemplary results will be presented here showing the effect of electromagnetic brakes or electromagnetic stirrers on the flow in the mold or illustrating the properties of two-phase flows resulting from an Ar injection through the stopper rod.

Using conventional grinding wheels, self-excited vibrations are one of the most limiting factors in terms of productivity and process stability in cylindrical plunge grinding. Depending on the dynamic behavior of the workpiece and machine, vibrations of the workpiece copy on the grinding wheel's surface, caused by uneven wear. This results in increasing waviness of the grinding wheel and by that, increasing workpiece vibration. Electromagnetic actuators are capable of influencing the dynamic process forces and therefore, the wear. The authors pursue the objective, to achieve an active control of the tool wear for low workpiece vibration and high workpiece quality. Therefore, a tool-wear-model which enables the estimation of the grinding wheel's surface is proposed. The parameterization of the model is realized carrying out a set of reference processes with subsequent identification. Aside from the dynamic tool wear, the workpiece oscillation is simulated by the model. A Kalman Filter is utilized to adjust the model onto the current process using the measured workpiece oscillation. Thus, it is possible to achieve an online estimation of the wave amplitude and phase angle on the grinding wheel's surface as well as their progression. © 2017 The Authors.

This work presents the model of a shear-frame-type structure composed of six flexible beams and three rigid masses. Fixed on the ground, outside the structure, two voltage-controlled electromagnetic actuators are used for vibration control. To model the flexible beams, unidimensional finite elements were used. Nonlinear equations for the actuator electromagnetic force, noise in the position sensor, time delays for the control signal update and voltage saturation were also considered in the model. For controlling purposes, a discrete linear quadratic regulator combined with a predictive full-order discrete linear observer was employed. Results of numerical simulations, where the structure is submitted to an impulsive disturbance force and to a harmonic force, show that the oscillations can be significantly reduced with the use of the electromagnetic actuators.

This report has its focus on development of an unconventional magnetic actuator for vehicular application more specific for gearbox actuators namely: Automatic Transmission Shifted by Wire (ATSbW). The application requires a compact an inexpensive electrically actuated drive that provides high torque over limited angle of movement. The specific research focus of this project is related to development of a novel and unconventional solution for a transmission actuator. The central part part of the system is an electromagnetic actuator that either directly performs the system requirements or is integrated into a mechanical transmission such as harmonic drive, cycloid gears, etc, to complete the task. Even though the project is connected into vehicular application it has bearing in robotics, mechatronics and so forth and on.

This report describes methods for retrofitting legacy hydraulic systems, particularly evaluating means for generating and verifying retrofit or new system design requirements. Methods that combine physics-based modeling, simulation, and design techniques are described and applied to a submarine control surface actuator retrofit problem. First, an integrated submarine/actuator subsystem model is developed for simulation-based design requirements generation. Simulations are used to derive power and energy storage requirements for control surface actuation during extreme submarine maneuvers, such as emergency surfacing. This study also investigated synthesis methods based on classical impedance synthesis techniques for realizing feasible actuator system configurations based on performance specifications. Application to disturbance rejection demonstrates resulting designs that are purely passive or fully active electromechanical systems. These methods can supplement designs proposed by domain experts, and enable means for choosing different configurations and for initially sizing system components.

Topology optimization methods suffer from a lack of convexity for the design of electromagnetic devices. Local minimizers indeed prevent deterministic methods from attaining the optimal solution. The optimization result may then vary according to the initial conditions. This paper proposes a convexityoriented method focusing on the maximization of the forces exerted on ferromagnetic parts in electromagnetic actuators. The method is based on a simultaneous optimization of two topologies by a gradient-based algorithm, the forces being computed by combining their magnetic fields within the Maxwell stress tensor. During the optimization, the two topologies converge towards a unique design using constraints whose shape is progressively modified. The method benefits from a fast convergence and produces consistent and efficient results, which is highlighted on a test problem. The method is eventually applied to a realistic problem related to the design of a switched reluctant actuator.

The goal of this research project is to develop a fuel injection system which delivers the desired ratio of air/fuel mixture to small scale internal combustion engines. Small scale engines require precise fuel control, but the fuel delivery system must be small and low-power. Our research is focused on the development of a planar fuel valve with high fuel delivery rates. The planar nature allows for successful system integration with small scale engines and systems. The fuel valve is electromagnetic, as electrostatic systems are not compatible with liquid fueled systems. The valve design is designed to have a very large open to closed fluidic resistance ratio such that when the system is not being operated, that the fuel delivery rate is near zero (i.e. the valve does not leak).

Active suppression of noise and vibrations is a well established field of research with many applications in acoustic and mechanical industries. In this paper we test some of these active control methods in order to assess their validity and performance when applied to electromagnetic fields. The application that we evaluated is a model of a mobile telephone equipped with one ordinary transmitting antenna and two actuator-antennas which purpose is to cancel out the electromagnetic field at a specific point in space (e.g. at your head).