IMEKO Event Proceedings

Page 849 of 866 Results 8481 - 8490 of 8655

A. Mariano, D. Dallet, Y. Deval, J-B. Bégueret

An advanced design methodology using a combination of behavioral models and transistor level models is presented in this paper. This methodology is very interesting for complex mixed-signal IC design, reducing the simulation time and improving the design flexibility. In order to validate the methodology proposed, a High-Speed Bandpass Continuous-Time Delta-Sigma Modulator is modeled. This modulator samples at high-IF signals, performing the direct conversion in the modern RF frontend receivers.

Nejmeddine Jouida, Chiheb Rebai, Adel Ghazel, Dominique Dallet

Continuous-Time delta sigma modulators (CT ΔΣM), by their nature, are mixed-signal systems. That fact creates a discontinuity in the traditional IC design flow which assumes that “discrete” and “continuous” time domain designs require separate design tools. In this work, we present a top level behavioral approach of modeling CT complex Bandpass (CBP) ΔΣM using VHDL-AMS language. The CT ΔΣ model can be used within the analog IC design environment. Fifth-order CT CBP ΔΣM which is tailor made for Bluetooth and WiFi Low-IF receiver demonstrates clearly the modeling technique.

Romano Giannetti, Mirko Marracci, Bernardo Tellini, Carmine Zappacosta

We analyse the volt-amperometric (VI-) method for the characterization of minor loops of soft magnetic materials. By adopting several input signals and by operating at various frequencies in the 10 Hz – 10 kHz frequency range, we perform the measurement on a soft ferrite core. Through the use of two different measurement schemes, we control in the first case the voltage across– and in the second case the current through– the primary coil. Measurement results are reported and a comparison among the various techniques is provided throughout the paper. A commercial ferrite core and a Fe-Si thin lamination are used as our samples.

Jaidilson Silva, Antonio Marcus Lima, Franz Neff, José Sérgio da Rocha Neto

The easy detection of fouling in duct systems is a persistent problem and remains a relevant demand for the chemical, oil, food and pharmaceutical industries. This work presents preliminary research results of vibrational hammer excitation for easy to use external non-invasive, non-destructive multi-layer fouling detection in pipelines and other large scale duct systems. Data were taken from the vibration amplitude and frequency variation in presence of an inner pipe fouling layer using acoustic accelerometer and microphone detection.

W. Steinchen, G. Kupfer, P. Mäckel

Digital Shearography, a laser interferometric technique in conjunction with the digital image processing, has the potential for vibration analysis due to its simple optical system and insensitivy against small rigid body motions. This paper will focus on its recent developments for vibration analysis and for nondestructive testing (NDT) by dynamic (harmonic) excitation. With the introduction of real time observation using automatically refreshing reference frame, both small and large rigid body motions are greatly suppressed. The development of a smaller and more mobile measuring device in conjunction with a user guided comfortable program Shearwin enables the digital shearography to be applied easily as an industrial on line testing tool.

Marc Seimert, Clemens Guehmann
Vibration based diagnostic of cracks in hybrid ball bearings

The paper presents a vibration based diagnostic system to detect cracks in balls of hybrid ball bearings. The diagnostic system based on a Bayesian Classifier. It is shown that it is able to separate healthy bearings from damaged balls and races. The system is tested with measurement data from a bearing test bench in different operating points of the bearing.

Vladimír Zábranský, Olga Tumová
Vibration Diagnostics of Electrical Rotating Machines

This article presents the vibration diagnostics of electrical rotating machines. The introduction describes the nature of the problem, state of the art in the field of vibration diagnostics, our contribution and achieved results. The theory of vibration is described in the second part. This part is divided into subsections called Harmonic oscillator, Forced vibrations, Free vibrations and Application. The third part deals with the measurement of vibration. In this part the answers to the most often asked questions related to the vibration measurement are listed. Facts introduced in this article are summarized in the conclusion.

Tassanai Sanponpute, Apichaya Meesaplak

Three ranges of Rockwell scale C reference hardness blocks: 20, 40, and 60 HRC were measured by deadweight-lever system hardness testing machine with two types of display: analog and digital. The testing machines were placed on the vibration table, whose frequency and amplitude of vibration can be controlled. Piezoelectric probe and vibration meter were used to confirm both amplitude and frequency of vibration. The hardness value at free from vibration is used as a reference to calculate the error of each hardness measurement at certain frequency and amplitude. Both machines give the same tendency. At vibration frequency higher than 15 Hz, there is no significant error of measurement in any vibration amplitude lower than 0.04 m/s² for all three hardness ranges. However, below 15 Hz vibration frequency, the negative error of both digital and analog displayed machine appears significantly higher and increases as the amplitude of vibration increases. Moreover, the softer range of hardness is more affected by the vibration. . Therefore, the result from this paper can be used as guideline for laboratory to control environmental vibration amplitude to be less than 0.01 m/s² for frequency (10 ± 5) Hz and 0.05 m/s² for other in Rockwell scale C hardness measurement.

Tassanai Sanponpute, Apichaya Meesaplak

The effect of environmental vibration on Vickers hardness machine is reported in this paper. Test force 9.807 N (HV1) and 98.07 N (HV10), representing low-force hardness test and normal hardness test, were selected for this experiment. Two machines with different loading mechanism made indentation under influence of single sinusoidal vibration with frequency ranging from 10 Hz to 100 Hz and amplitude ranging from 0.002 m/s² to 0.04 m/s². Indentations were captured by CCD camera and diagonal lengths were measured automatically by software. Response to vibration for each loading mechanism, hardness level, and test force level is discussed in this paper. This experiment shows that the relative errors are higher than maximum permissible error in ISO 6507-2 when vibration amplitude higher than 0.005 m/s² or 0.0005 gn. Result from this paper can be used as a guideline to revise maximum allowable vibration acceleration and test force scale to which the limit should be applied.

Domenico Capriglione, Marco Carratù, Marcantonio Catelani, Lorenzo Ciani, Gabriele Patrizi, Antonio Pietrosanto, Paolo Sommella
Vibration Step Test for Performance Analysis of Inertial Measurement Unit

Nowadays Inertial Measurement Units are largely implemented in several applications, such as automotive and self‑driving vehicles, Unmanned Aerial Vehicles, cellular phones, robotics, artificial intelligence and many others. Despite this, recent literature doesn’t cover properly both the characterization of the dynamical metrological performances and the reliability analysis when microelectronic devices operate under real environmental conditions. Trying to fill this gap, the characterization of an Inertial Measurement Unit under vibration condition is proposed in this work by means of a step-test vibration profile to test the behavior of an inertial platform subjected to a sinusoidal vibration at different frequencies. Starting from the widely known sine sweep vibration profile, a customized test plan has been developed basing on a frequency step up of a sinusoidal stimulus over time to investigate the frequency response of the inertial platforms. The application to a set of real devices has confirmed that the proposed test allows identifying the effects of mechanical stress on the metrological performances of microelectromechanical sensors over a frequency domain. The developed test plan could also be used to investigate whether or not sinusoidal vibrations at certain frequencies trigger some failure mechanisms that are normally quiescent.

Page 849 of 866 Results 8481 - 8490 of 8655