NVH FOR VEHICLES: TESTING AND SIMULATION
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- Versione italiana
- Academic year
- 2020/2021
- Teacher
- EMILIANO MUCCHI
- Credits
- 12
- Didactic period
- Annualità Singola
Training objectives
- Provide advanced experimental and numerical methods for NVH (Noise Vibration and Harshness) and comfort issues in the automotive field.
Processing of experimental vibro-acoustic data in an autonomous way for the identification of the main sources of noise and vibration in vehicles.
Use of advanced instrumentation for the experimental characterization of the NVH impact of vehicles.
Knowledge of acoustic and vibration propagation inside materials in order to design noise and vibration abatements in vehicles.
Simulate the dynamic behavior of mechanical systems by finite element analysis and multibody analysis. Prerequisites
- Mechanical vibrations
Course programme
- MODULE 1 Testing (First Semester)
The physics of sound, definition of the main acoustics properties, frequency analysis, noise propagation in free field and confined areas, instrumentation and measurement techniques.
Noise generation and propagation in mechanical systems for automotive applications.
Experimental vibration analysis and experimental modal analysis of mechanical systems: theory and experimental testing.
NVH experimental tests in operational conditions:
Noise measurements in the passenger compartment, acceleration measurements, pass-by measurements.
Experimental test with shut down vehicle: acoustic isolation tests, transfer path analysis, experimental modal analysis with impact hammer and electrodynamic skater, FRF test for dynamic stiffness evaluation.
Vibration characteristics of internal combustion engines and rotating components (waterfall plot, order tracking).
Accelerated life testing for durability analysis of critical components in the automotive field (MIMO-SOMO environmental testing)
Laboratory: vibro-acoustic testing in anechoic chamber; experimental modal analysis of a chassis; dynamic stiffness testing; accelerated life testing with vibrating table; acoustic testing in components.
MODULE 2 Simulation (Second Semester)
Overview of FEM / BEM / SEA simulation techniques for automotive applications;
FEM acoustic modeling for automotive applications (cockpit, silencers);
Advanced modeling of finite elements for dynamic analysis of automotive components such as car frames and critical components;
Theoretical models for predicting acoustic properties of porous and multilayer systems;
Vibration suppression (design and methods for experimental testing of vibration dampers);
Active noise control.
Laboratory: computer simulation activities with FEM software with automotive applications
Seminars: short seminars will be held during the course by automotive industry staff. Didactic methods
- The course includes: theoretical lectures made with the aid of multimedia systems, training and laboratory activities related to the realization of technical reports on vibro-acoustic testing of vehicles, experimental modal analysis of a chassis, accelerated life testing; technical seminars by specialists and educational visits at local companies.
Deliverables are: technical reports regarding the experimental tests and numerical simulations carried out in the laboratories; a speech of 15 minutes regarding one experimental technique explained during the course (module 1) and a speech of 15 minutes regarding one numerical simulation performed during the course (module 2) Learning assessment procedures
- The exam includes an oral test for each module (testing and simulation).
Each oral exam, for testing the understanding and application of the course content, consists of two parts: a 15-minute oral speech regarding one experimental technique explained during the course, to be held in the classroom; an oral test regarding the course contents.
The exam is passed if the score of each test is at least sufficient. The final mark is the arithmetic mean of the marks obtained in the two tests. Reference texts
- Lecture notes by teachers
Other recommended textbooks:
For study
Mechanical Vibrations (6th Edition), Singiresu S. Rao, ISBN-13: 978-0134361307.
Noise and Vibration Analysis: Signal Analysis and Experimental Procedures, Anders Brandt, ISBN: 9780470746448.
J. F. Allard, N. Atalla, Propagation of Sound in Porous Media: Modelling Sound Absorbing Materials, Second Edition, John Wiley & Sons, Ltd, 2009
For the personal deepening of contents:
Random Vibration and Shock Testing, Wayne Tustin.
Vibration monitoring, testing, and instrumentation, Clarence W. de Silva.
Vibration damping of structural elements, C. T. Sun, Y. P. Lu
Passive vibration isolation, Eugene I. Rivin
Vibration damping, control, and design, Clarence W. de Silva
Vibration: fundamentals and practice, Clarence W. de Silva
Modal analysis, Jimin He and Zhi-Fang Fu
