Improved Microtransformer Design Utilizing Fe-Co Magnetic Core

This paper presents the design, fabrication, and characterization of on silicon integrated micro-transformers for high frequency power applications. This device has stable characteristic of L versus f up to frequencies higher as 50 MHz. The design is improved, so that the electrical resistance of coils is reduced and current capability is increased. The microtransformer shows an inductivity of about 50 nH, resistance of 350 mΩ and can be applied for current up to 1.5 A

Miniaturized push-button rotational energy harvesting generator

This work presents a development and miniaturization of a rotational electromagnetic energy harvesting (EH) generator. The energy harvesting generator is driven mechanically by pushing the button. The energy harvester system has an integrated mechanism for movement conversion. This mechanism converts the linear movement of the button into rotation with a rotational speed of 1000 rpm. An electromagnetically part of harvester consists of in FR-4 embedded multilayer planar coils and of multipole NdFeB hard magnets. The miniaturized energy harvester generates a maximum open circuit output voltage of about 500 mV with duration of about 2 s and a maximum short circuit output current higher than 40 mA

Thin-Film Microtransformer for High Frequency Power Applications

This paper describes a development of a microtransformer device fabricated using thin film technology. The device is designed for higher switching frequencies beyond to 50 MHz power applications. A especially by the microtransformer is a design, which allows wide flexibility of a device by choosing a different values of an inductance and of a windings ratio. The microtransformer device is integrated on silicon substrate consisting of a closed magnetic core and six coils. Both, primary and secondary device side consist three coils. Therefore, this design allows using of a device for different switching frequencies. As a magnetic material for transformer core a permalloy NiFe45/55 was chosen

Thin-Film Microtransformer for High Frequency Power Applications

This paper describes a development of a microtransformer device fabricated using thin film technology. The device is designed for higher switching frequencies beyond to 50 MHz power applications. A especially by the microtransformer is a design, which allows wide flexibility of a device by choosing a different values of an inductance and of a windings ratio. The microtransformer device is integrated on silicon substrate consisting of a closed magnetic core and six coils. Both, primary and secondary device side consist three coils. Therefore, this design allows using of a device for different switching frequencies. As a magnetic material for transformer core a permalloy NiFe45/55 was chosen

Failure of mounting bolt of helicopter main gearbox support strut

The mounting bolt of helicopter main gearbox support strut was fractured into two pieces during the flight mission. The fracture occurred at the root of the first engaged thread of the bolt-nut assembly. Visual inspection of the fracture zone revealed cracks, formed by interlinking of corrosion pits, at the almost all thread roots of the bolt. Energy dispersive spectroscopy disclosed significant damage of the cadmium plating as well as the presence of large amounts of corrosion products at the bolt threads. Through the fractography and metallography analysis, it was found that the mounting bolt failed due to hydrogen-induced intergranular stress corrosion cracking (HI-IGSCC). The finite element (FE) analysis confirmed that the crack origin was located at the area with the maximum tensile stress in the bolt. (C) 2016 Elsevier Ltd. All rights reserved

Characterization of laser beam interaction with carbon materials

This paper presents simulation and experimental results for the exposure of some carbon-based materials to alexandrite and Nd3+:YAG (yttrium aluminum garnet) laser radiation. Simulation of the heating effects was carried out using the COMSOL Multiphysics 3.5 package for samples of carbon-based P7295-2 fiber irradiated using an alexandrite laser and carbon-based P4396-2 fiber irradiated using an Nd3+:YAG laser, as well as by applying finite element modeling for P7295-2 samples irradiated using an Nd3+:YAG laser. In the experimental part, P7295-2 samples were exposed to alexandrite laser radiation while samples of carbon-based composite 3D C/C were exposed to Nd3+:YAG laser radiation. Micrographs of the laser induced craters were obtained by light and scanning electron microscopy, and the images analyzed using the ImageJ software. The results obtained enable identification of the laser-material interaction spots, and characterization of the laser induced changes in the materials investigated