The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The switch mode power supply (SMPS) have been widely used in the electrical and electronics systems for AC-DC and DC-DC power conversion, which can generate a lot of electromagnetic interference (EMI), especially conducted emission (CE) from 9kHz to 30MHz. The traditional CE models and mechanisms have been present for three line systems, including live, neutral and ground lines, while a novel CE models...
For the radiated EMI technology of smart grid equipments, the modeling and features on the interference noise are analyzed in this paper. On the basis of radiated EMI mechanism analysis on the electronic equipments, considering of the special features of smart grid, the chip interference mode and structure interference model are established according to the characteristics of radiated electromagnetic...
In practical application of electro-mechanical impedance (EMI) technique, the monitored structure is constantly undergoing change due to external boundary conditions and the surrounding ambience. This change, in most cases, is considered to be normal and a part of the everyday use of the structure. The aim of this paper is to examine and obtain a better understanding of practical issues that are a...
An accurate electro-mechanical impedance (EMI) model for analytical crack detection of a Timoshenko beam is established based on the improved reverberation-ray matrix method via the recursive formulations. The crack is treated as a massless rotational spring. A pair of PZT patches with free ends symmetrically bonded onto the beam is assumed in a state of pure one-dimensional axial motion under an...
It is the first time that the Antarctic super low frequency (SLF) and extremely low frequency (ELF) radio atmospheric noise has been measured in China. The time domain profile and the frequency domain profile of the data have been gained by analyzing and processing the measured data, and the change characteristic of the radio atmospheric noise has been discussed along the day, night and the frequency...
Two-current probes method and S-parameter method are studied comparatively for conductive EMI noise source modelling in this paper. Firstly, the basic theory of the two-current probes method and S-parameter method are introduced for noise source impedance extraction. Secondly, ZX and Zsetup are important intermediate results in the two methods, therefore their extractions are analyzed respectively...
In the paper, a fast approach is proposed to identify the mechanism for radiated EMI using near field measurement. Equivalent radiation models have been set up to analyze radiated source, which include electric dipole (Common Mode) and magnetic dipole (Differential Mode). In near field region, according to wave impedance theory, mechanism of radiated noise can be identified and noise reduction methods...
A new approach to conducted EMI noise separation is presented for EMI noise diagnosis based on blind signal separation algorithm in cooperation with the use of current probes in time domain measurement. In this paper, firstly the principle of BSS is introduced and then, the implementation of BSS for conducted EMI noise separation is described in detail. Experiment results show that by using BSS algorithm,...
A hybrid method combining electro-mechanical impedance (EMI) technique and artificial neural network (ANN) is proposed to detect damages in structural systems. The structural members are treated as Timoshenko beams for flexural motion as well as the damages are modeled by changes in Young's modulus in the damaged area. For a structural member with surface-bonded PZT wafers, a coupled system is considered...
A modified model combining EMI technique and RMM is proposed to quantitatively correlate crack parameters with piezoelectric signatures for structural health monitoring. The structural members are modeled as Timoshenko beams for flexural motion and as the classical longitudinal rods for axial motion as well as the cracks are treated as massless rotational springs. For a structural member with surface-bonded...
This paper focuses on the delamination detection in composite beams using electro-mechanical impedance (EMI) signatures, which is directly related to the structure's mechanical impedance. A model of a laminated beam including a delamination as well as installed PZT transducers is presented. Furthermore, the model has to take into account the dynamic behavior of the piezoelectric patches and simulate...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.