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Vehicle Gearbox Noise and Vibration : Measurement, Signal Analysis, Signal Processing and Noise Reduction Measures.
Advances in methods of gear design and the possibility of predicting the sound pressure level and life time of gearboxes and perfect instrumentation of test stands allows for the production of a new generation of quiet transmission units. Current literature on gearbox noise and vibration is usually...
| Clasificación: | Libro Electrónico |
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| Autor principal: | |
| Formato: | Electrónico eBook |
| Idioma: | Inglés |
| Publicado: |
Hoboken :
Wiley,
2014.
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| Colección: | Automotive Series.
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| Temas: | |
| Acceso en línea: | Texto completo |
Tabla de Contenidos:
- Vehicle Gearbox Noise and Vibration; Contents; Series Preface; Preface; Acknowledgements; 1 Introduction; 1.1 Description of the TATRA Truck Powertrain System; 1.2 Test Stands; References; 2 Tools for Gearbox Noise and Vibration Frequency Analysis; 2.1 Theory of Digitisation of Analogue Signals; 2.1.1 Types of Signals; 2.1.2 Normal Distribution; 2.1.3 Mean Value and Standard Deviation (RMS) of a General Signal; 2.1.4 Covariance; 2.1.5 Mean Value and Standard Deviation (RMS) of a Sinusoidal Signal; 2.1.6 Digitalisation of Signals; 2.1.7 Signal-to-Noise Ratio; 2.1.8 Sampling as a Mapping.
- 2.2 Nyquist-Shannon Sampling Theorem2.2.1 Antialiasing Filter; 2.2.2 Sound and Vibration Measuring Chain; 2.3 Signal Analysis Based on Fourier Transform; 2.3.1 Time and Frequency Domain; 2.3.2 Fourier Series for Periodic Functions; 2.3.3 Fourier Transform of the Continuous-Time Functions; 2.3.4 Short-Time Fourier Transform; 2.3.5 Fourier Transform of the Discrete-Time Functions; 2.3.6 Inverse Fourier Transform of the Discrete-Time Functions; 2.3.7 DFT of a Constant and a Cosine Signal; 2.3.8 Phasors as a Tool for Modelling Harmonic Signals; 2.3.9 Example of DFT Calculation.
- 2.3.10 Time and Frequency Scales2.3.11 Spectral Unit of Autospectrum; 2.3.12 Cross-Spectrum; 2.3.13 Calculation of the Inverse Discrete Fourier Transform; 2.3.14 Fast Fourier Transform; 2.3.15 Time Window; 2.3.16 Calculation of the Signal Power; 2.3.17 Frequency Weighting; 2.3.18 Analysis of Random Signals with the Use of Averaging in the Frequency Domain; 2.4 Zoom FFT; 2.4.1 Real-Time Zoom; 2.4.2 Non-Destructive Zoom; 2.5 Filtration in the Frequency Domain; 2.5.1 Filtering; 2.5.2 Integration and Calculation of Derivatives; 2.6 Average Power of the Signal; References.
- 3 Gearbox Frequency Spectrum3.1 Source of Gearbox Noise and Vibration; 3.2 Spectrum Signature; 3.3 Low Harmonics of the Shaft Speed; 3.4 Harmonics of the Fundamental Toothmeshing Frequency and their Sidebands; 3.5 Subharmonic Components; 3.5.1 Hunting Tooth Frequency; 3.5.2 Effect of the Oil Film Instability in Journal Bearings; 3.6 Ghost (or Strange) Components; 3.7 Gear Rattle; 3.8 Periodicity in Signals Measured on a Planetary Gearbox; 3.9 Spectrum Components Originating from Faults in Rolling Element Bearings; 3.9.1 Calculations for Bearing Defect Frequencies.
- 3.9.2 Envelope Frequency AnalysisReferences; 4 Harmonics and Sidebands; 4.1 Harmonics; 4.2 Sidebands; 4.2.1 Amplitude Modulation; 4.2.2 Phase Modulation; 4.2.3 Mixed Modulation; 4.3 Analytic Signal; 4.3.1 Definition of Hilbert Transform; 4.3.2 Calculation of Hilbert Transform of Sampled Signals; 4.3.3 Demodulation of the Modulated Harmonic Signal; 4.3.4 Unwrapping Phase; 4.3.5 Normalising Phase; 4.3.6 An Alternative Computing the Instantaneous Frequency; 4.3.7 Envelope Analysis; 4.4 Cepstrum; 4.4.1 Effect of Harmonics; 4.4.2 Effect of Sideband Components; 4.4.3 Advantages of Cepstrum.