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During the launching of the AUV especially in air-launching, the water entry problem is inevitable. The AUV will stir the flow field of surrounding fluid during the moving into water, while the fluid will act a strong force on the AUV in return, which may cause trajectory deflection problems or damage to their structure and inner components in severe cases. The water entry experiment of full-size...
Recently, coastal city and facilities had many damages by abnormally high waves with climate change. Especially, breakwater systems based on a caisson-type harm damages in Korea because they are located in the outside port. In order to reduce theses damages, new type breakwater systems using interlocking caisson are researched. Generally, caissons of breakwater system were constructed on crushed rock...
The thin-walled parts of the tank are widely used in aerospace filed and the accuracy is the basis requirement for ensuring the usability. Due to the low rigidity of the thin-walled parts, the milling force becomes a major factor for the machining deformation. Based on analysis the relationship between feed speed and the length of the cutting arc, the feed speed optimization method is proposed to...
As the air bearing flying height (a few nanometer levels) and the deformation of suspensions (micro-or millimeter level) run at two different scales, a dual-scale model for head disk interface (HDIs) has been proposed to analyze the unloading behavior of a subambient pressure slider. With the scheme developed, the unloading process can be simulated efficiently. The nonlinear vibrations of the air...
There will always have a greater residual stress in the processing process of the micromechanical gyroscopes straight elastic-beam. affecting the performance of micromechanical gyroscopes. According to the principle of stiffness equivalence, the original elastic-beam of the micromechanical gyroscope is improved to the beam of drive as the U-beam and sense as the carb-leg beam by the combination of...
The induction motor with skewed rotor bars is an effective motor structure for eliminating the slot harmonic fields, and the resulting noise and vibration. 2-D multi-slice finite element method (FEM) is typically used to analyze the performance of the induction motor with skewed rotor bars. However, in order to achieve high accuracy, the number of the slices is generally very high, which is also a...
In this paper, three different models of friction in presliding regime on linear motor platform are deduced according to basic physical laws, which are named as the Kelvin model, the modified Kelvin model and the four-element model. To validate the effectiveness of these models, the particle swarm optimization is applied to determine the coefficients in each model. Then experiments of ramp input force...
Based on theoretical analysis and experimental research short-circuit electromagnetic forces of three-phase medium voltage (MV) earthing switches (ES) with different motion forms and different structural arrangements of ground loop have been studied. And the influence of electromagnetic force under correspondent various conditions on short-circuit making performance is discussed in detail as well...
Permanent magnet track linear motor drives offer a cost-effective motion control solution in numerous industrial manufacturing processes, covering a wide range of material handling and conveyor applications. To further reduce the initial costs of a permanent magnet track linear motor drive system, discontinuous magnet tracks can be considered. However, in a discontinuous magnet track, the armature...
Based on nano two-phase composite magnetic material, a design and optimization scheme of energy-saving wind power grid contactor is proposed, which solves the problems of traditional contactor's high iron loss, low speed and large AC noise. In this paper, the electromagnetic system of the contactor is redesigned by the characteristics of high remanence, high coercivity and wide hysteresis loop of...
Side reservoir can improve electromigration (EM) lifetime of copper interconnects. In this work, finite element method (FEM) simulations for interconnect structures with cathode end-of-line reservoir and side reservoir respectively have been conducted to study the side reservoir effects on EM lifetime. It is demonstrated that side location is most likely to have void failure and side reservoir can...
The paper proposes an optimized geometry for a DC electromagnet combining the experimental design (DOE) and FEM. The optimization problem takes into account three geometrical parameters (coil shape ratio, support thickness ratio and support height ratio) and consists in maximization of the acting force related to the largest air-gap, preserving the global dimensions of the device (external radius,...
In the operation of bulldozer, the working device bears various complex loads, which raise higher demands on the rationality of the structural design, the convenience of the operation, the durability and the reliability of the working device. The finite element method is used to analysis the structural strength and the fatigue life of the working device. The dangerous points, stress, strain distribution...
In this paper, the dynamic characteristics of two types of electromagnetic repulsive force actuators are compared using the simulation of finite element method. The two electromagnetic repulsive force actuators are equipped with a single-sided coil and a double-sided coil respectively. Initially, the construction and theory of each of the electromagnetic repulsive force actuators are discussed. Subsequently,...
This paper studied the optimization of the shunt release electromagnet based on Ansoft maxwell finite element simulation. The minimum size as the optimization target by taking into account the electromagnet force and temperature rise limit. In this study the electromagnetic force is calculated using finite element simulation, demand of temperature rise limit is satisfied by limiting the maximum current...
The circuit breaker is an important part of control and protection in the power system. Mechanical failure is the main fault of circuit breakers, and the loosening of fasteners is one of the typical mechanical faults. The self-loosening of bolted joints is closely related to the vibration, especially transverse vibration. There is strong vibration while the circuit breakers are opened and closed....
This paper describes the prediction and prevention of losing steps in helical teethed linear actuator (HTLA) for artificial muscle. When the rapid external force is applied to the HTLA, it becomes a state of losing steps. Therefore, it is important to predict and prevent this phenomenon. First, we clarified the phenomenon of losing steps in the HTLA by using numerical simulation with 3-D FEM. Next,...
A novel concept of modular bistable electromagnetic actuator in valve operation is numerically analysed, designed and experimentally tested. The actuator takes advantage of permanent magnets for assuring stable positions of the valve body and field coils for control of the valve operation. The paper presents the basic concept of the actuator together with its numerical investigation for the case of...
A new cantilever-beam nonlinear electromagnetic vibration energy harvester with noticeable effects of complex motion composed of relative displacement and torsion of the vibrating element is considered. The analysis of frequency characteristics carried out using the finite element models shows significant differences regarding generated output voltage and frequency bandwidth when detailed 2-d variations...
Double-sided coreless linear motors have a crucial role in direct-driven precise linear motion applications. In this study, an optimum design effort focused on thrust force production is presented. For an applicable brushless linear motor structure, winding and permanent magnet (PM) dimensions which are providing the highest possible force are defined by using finite element analysis (FEA). It is...
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