93825 - ACUSTICA DEL VEICOLO M

Learning outcomes

The students will be able to characterize, modify and simulate the acoustic emissions of vehicles, integrating these with other technical skills. The learning oucomes include: fundamentals of acoustics; NVHanalysis; vehicle noise control (with laboratory activity); acoustic virtual reality applied to vehicles (with laboratory activity); increasing the acoustic comfort on vehicles; basic knowledge of measuring equipment and technical standards.

Course contents

1. Physical acoustics.

Main acoustic quantities (pressure, particle velocity, sound speed, sond intensy, etc.).

Acoustic impedance and electrical analogy.

Doppler effect.

Wave equation and solutions outdoors and indoors. Plane, spherical, cilidrical waves. Standing waves, interference, "anti-sound". Ray approximation. Scattering and diffraction.

2. Sound levels, decibel and spectra

Sound signal characteristis. Decibels. Basic of frequency analysis. Spectra. Filters. Weighting curves. Sound level metrics.

3. Electroacoustic transducers

Loudspeakers. Microphones. Accelerometers.

4. Measuring equipment

Sound level meters. Real-time and FFT analyzers. Sound intensity meters. Digital recording and playing. Calibration. Law and technical standards.

5. Sound-materials interaction

Acoustics at the fluid-solid interface (absorption, reflection, transmission, diffusion).

Sound absorption: basic laws and control mechanics.

Sound insulation: basic laws and control mechanics.

6. Sound generation and control in vehicles

Powertrain and exhaust noise.

Noise from the wheel/road interaction.

Aerodynamic noise.

Noise control solutions.

7. Sound quality of vehicles

NVH descriptors.

Sound power measurements according to ISO 3741 (Laboratory).

Pass-by noise and vehicle homologation.

Road surface effects (ISO 362, ISO 10844 ecc.).

Examples : mufflers, mechanical components, etc. (Laboratory).

8. Virtual acoustics and simulation

Human hearing system. Monoaural and binaural hearing.

Characterization of a sound source (Laboratory).

Characterization of the environment (Laboratory).

Virtual reproduction techniques (HOA, VBAP, ecc.).

Acoustic virtual model of a vehicle (Laboratory).

9. Seminars helds by experts in the automotive sector

This program may be subject to changes before the beginning of the lectures.

 

 

 

 

 

 

 

Readings/Bibliography

Copy of the slides shown during lessons, in pdf format.

L.L. Beranek (editor), Noise and vibration control, Revised Edition, Institute of Noise Control Engineering, Washington, DC (1988).

Other books will be suggested during the lessons.

Teaching methods

Lectures, in presence and/or on line.

Examples worked out during the lectures.

Laboraory activities, using measuring equipment and specialized software.

Assessment methods

The final exam includes:

1. a written test (40 min). Closed books. Minimum score: 18/30.

2. an oral test (20 min).

Students who fail in the written test (score < 18/30) cannot proceed to the oral test and shall repeat the full exam.

The final score is a balanced evaluation of the written and oral tests.

Teaching tools

PC, Applied Acoustics laboratory, software for audio signal processing and virtual reality.

Office hours

See the website of Massimo Garai