Combustion mechanical noise breakdown – turbocharger noise identification on a V8 engine

2019 ◽  
pp. 171-187
Author(s):  
Karl Janssens ◽  
Fabio Bianciardi ◽  
Konstantinos Gryllias ◽  
Simone Delvecchio ◽  
Claudio Manna
Keyword(s):  
Mechanical Noise ◽  
Noise Identification

Mechanical Noise Identification Using Time-Frequency Representations

2001 ◽  
Author(s):  
Min-chun Pan
Keyword(s):  
Computation Time ◽  
Fan Noise ◽  
Time Frequency ◽  
Mechanical Noise ◽  
Machine Element ◽  
Electrical Vehicles ◽  
Original Scheme ◽  
Dynamic Signature ◽  
Noise Identification ◽  
Velocity Transmission

Abstract Three computation schemes of time-frequency representations (TFRs) have been developed and implemented to identify different components of mechanical noise originated from the transmission system of electrical vehicles. This study explores the close relationships between three TFRs, i.e. the spectrogram based on windowed Fourier transform (WFT), the Wigner-Ville distribution (WVD), and the smoothed WVD (SWVD). One main purpose is to pursue the efficiency of computing the SWVD of a dynamic signature. The revised scheme can tremendously reduce the computation time to a scale of around 1/90, compared with the original scheme. To assess the validation of these TFR schemes, firstly, four synthetic signals are designed and processed. Secondly, the developed TFRs are applied to distinguish different spectral components of transmission noise, and identify their sources. This study takes an electrical scooter with a continuous velocity transmission (CVT) system as a test bench. The CVT-belt noise, helical-gear whine noise, and fan noise can be clearly identified via the processing of the TFRs. These obtained conclusions can be used as references for machine element modification to improve annoying noise.

Measurement of thermal-mechanical noise in microelectromechanical systems

2002 ◽  
Vol 81 (10) ◽  
pp. 1779-1781 ◽  
Author(s):  
T. H. Stievater ◽  
W. S. Rabinovich ◽  
H. S. Newman ◽  
R. Mahon ◽  
P. G. Goetz ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Mechanical Noise

Experimental Investigation of Vibration and Noise Control of Reciprocating Compressors

2012 ◽  
Vol 443-444 ◽  
pp. 837-842
Author(s):  
Jiang Qi Long ◽  
Si Jia Zhou ◽  
Ping Yu
Keyword(s):  
Experimental Investigation ◽  
Noise Control ◽  
Inertia Force ◽  
Reciprocating Compressor ◽  
Working Process ◽  
Noise And Vibration ◽  
Mechanical Noise ◽  
Compressor Piston

The reciprocating compressor contains crank-rod mechanism whose unbalanced inertia force mainly accounts for mechanical noise and vibration during the working process. Through the analysis of fit between the diameter of the compressor piston and the crank eccentricity, influence of imbalance force on the compressor vibration and noise is obtained under no change in other parts. The tests of vibration and noise are followed for the purpose of verification. The results show that the vibration and noise control will be better if a small piston diameter and a big crank eccentricity are utilized.

Incubator Noise

PEDIATRICS ◽  
1975 ◽  
Vol 56 (4) ◽  
pp. 617-617
Author(s):  
Gōsta Blennow ◽  
Nils W. Svenningsen ◽  
Bengt Almquist
Keyword(s):  
Low Frequency ◽  
Sound Level ◽  
Noise Levels ◽  
Frequency Sound ◽  
Mechanical Noise ◽  
Sound Levels ◽  
Infant Incubator ◽  
Improved Model ◽  
Model C

Recently we reported results from studies of incubator noise levels.1 It was found that in certain types of incubators the noise was considerable, and attention was called to the sound level in the construction of new incubators. Recently we had the opportunity to study an improved model of Isolette Infant Incubator Model C-86 where the mechanical noise from the electrically powered motor has been partially eliminated. With this modification it has been possible to lower the low-frequency sound levels to a certain degree in comparison to the levels registered in our study.

scholarly journals Talin Folding as the Tuning Fork of Cellular Mechanotransduction

2020 ◽  
Author(s):  
Rafael Tapia-Rojo ◽  
Alvaro Alonso-Caballero ◽  
Julio M. Fernandez
Keyword(s):  
Bandpass Filter ◽  
Tuning Fork ◽  
Frequency Range ◽  
Periodic Force ◽  
Binding Partners ◽  
Mechanical Noise ◽  
Cellular Mechanotransduction ◽  
Folding Dynamics ◽  
Mechanical Information ◽  
Biological Environment

Cells continually sample their mechanical environment using exquisite force sensors such as talin, whose folding status triggers mechanotransduction pathways by recruiting binding partners. Mechanical signals in biology change quickly over time and are often embedded in noise; however, the mechanics of force-sensing proteins have only been tested using simple force protocols, such as constant or ramped forces. Here, using our magnetic tape head tweezers design, we measure the folding dynamics of single talin proteins in response to external mechanical noise and cyclic force perturbations. Our experiments demonstrate that talin filters out external mechanical noise but detects periodic force signals over a finely-tuned frequency range. Hence, talin operates as a mechanical bandpass filter, able to read and interpret frequency-dependent mechanical information through its folding dynamics. We describe our observations in the context of stochastic resonance, which we propose as a mechanism by which mechanosensing proteins could respond accurately to force signals in the naturally noisy biological environment.

scholarly journals Improving postural control by applying mechanical noise to ankle muscle tendons

2016 ◽  
Vol 234 (8) ◽  
pp. 2305-2314 ◽  
Author(s):  
Liliane Borel ◽  
Edith Ribot-Ciscar
Keyword(s):  
Postural Control ◽  
Mechanical Noise ◽  
Ankle Muscle
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