Politecnico di Torino | |||||||||||||||||
Anno Accademico 2011/12 | |||||||||||||||||
01OFGLO Car body design and aerodynamics |
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Corso di Laurea Magistrale in Ingegneria Dell'Autoveicolo (Automotive Engineering) - Torino |
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Presentazione
This module provides information regarding the design of the vehicle bodywork keeping in mind the various functions involved. the areas covered include ergonomics, climatic, acoustical and vibrational comfort, layout of the structure and safety.
It provides the concepts of aerodynamic behaviour in motor vehicles and its methods of analysis and numerical and experimental optimization, in harmony with the style and architectural needs. On the course, the influence of the aerodynamics with regards to comfort and the cooling systems will also be affronted. |
Risultati di apprendimento attesi
Students should acquire skills in the area of bodywork design with particular reference to bodywork functions.
Metodology of vehicle aerodynamics, experimental techniques in wind tunnel and CFD (Computational Fluid-Dynamics) instruments of calculation used for the motor vehicle. |
Prerequisiti / Conoscenze pregresse
Knowledge of fluid mechanics and the numeric calculus methods.
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Programma
1 - Introduction
Prerequistes and functions of the motor vehicle from the bodywork point of view. 2 – Ergonomics and use of space Principles of posture Principles of human vision Principles of movement Percentiles and manikins used Seating position Livability Accessibility External and Internal visibility Manoeuvrability and command access Loading and unloading of goods 3 – Climatic comfort Physiological principles of climatic comfort Criteria for measuring flows 4 – Structural integrity Bodywork design: construction details for hatchbacks and saloons, spiders, MPVs, commercial vehicles, lorry cabs. Examination of influencing external loads; evaluation of internal loads; evaluation of external loads Simplified model for the functional analysis of the car structure when subject to internal and external loads Torsional behaviour Flexural behaviour 5 – Acoustical and vibrational behaviour Principles of the physiology of the human ear and noise quality Vibration and noise sources Dynamic behaviour of the bodywork and modal analysis Engine suspension Squeaks and rattles Noise diffusion via air Acoustic insulation 6 - Safety Preventative, active and passive safety Passive safety: reference to international standards Crashes of small intensity Crash tests External illumination and signal devices ; reference to international standards Prerequisites and evaluation of devices. 1. Reference to fluid-dynamics Equations of movement for uncompressible and compressible fluids. Limited laminar and turbulent layers Concepts of resistance from friction and pressure. Criteria for similarities 2. Aerodynamic resistance Resistance to movement. Effect on consumption and performance. Flow structure around squat bodies Contributions to the aerodynamic resistance and parameters of synthesis. Influence on the aerodynamic performance of significant variations of shape. Resistance in commercial and industrial vehicles. 3. Aerodynamic problems inherent to the dynamic behaviour, to the comfort and to the cooling Aerodynamic noise. Stability with lateral wind. Lift decrease for high performance vehicles. Engine cooling Brake cooling. Aerodynamic forces on the bodywork. Soiling and dispersion of exhaust fumes. 4. Experimental aerodynamics Automobile wind tunnels. Tests on scale models. Measurement of the strength and aerodynamic torque. Techniqu es for measuring the fluid-dynamic size (pressure, speed, heat cables, LDV, PIV). Analysis of aerodynamic noise. Analysis of air flows under the bonnet Road tests. 5. Computational aerodynamics Numeric methods for equations of fluid motion. Calculations grids and their creations based on CAD geometry. Examples of turbulence. Surrounding conditions. Elaborations and visualization of the results. 6. Aerodynamic development of vehicles Simultaneous development of aerodynamic forms, style and planning of the vehicle. Improvement of the form and interaction with the style. Varying evaluations of the shaft and lateral winds. Optimization of the additions. Reduction of the bodywork resistance. |
Organizzazione dell'insegnamento
Students carry out practical work on the following:
Ergonomical evaluation of a vehicle; postural comfort; external visibility Evaluation of the torsional stiffness of a bodywork via a simplified model and identification of the possible improvements. Applicable examples of the calculus codes CFD. Instrumentation of measure for calibration. Measuring of pressure field on scale models. |
Testi richiesti o raccomandati: letture, dispense, altro materiale didattico
Folders of notes are available for the students.
Texts for further information : J. Fenton, "Handbook of Vehicle Design Analysis", SAE, 1999 W. Karwowsky, "Automotive Ergonomics", Taylor & Francis, 1993 J. Happian-Smith e altri, "An Introduction to Modern Vehicle Design", SAE, 2002 T. Gillespie, "Fundamentals of Vehicle Dynamics", SAE, 1999 Hucho W. H. – Aerodynamics of Road Vehicles Pope-Rae – Low Speed Wind Tunnel Testing |
Criteri, regole e procedure per l'esame
Parte: Car Body Design (Tonoli)
Esame: scritto + orale opzionale per chi ha superato lo scritto con votazione >=27 - tipo di prova (esercizi, quiz o test a riposta multipla, ecc.): 3 o 4 domande aperte - sempre la durata della prova (orientativa); 2 ore - sempre se si possono usare materiali/testi/dispense/formulari, o no; non si può utilizzare alcun materiale. I fogli sono forniti dal docente - la valutazione massima; 30L - la soglia di ammissione all'orale, nel caso; 27 il voto orale può portare ad un aumento o una diminuzione del voto scritto. - quanto la valutazione dello scritto pesa nella definizione del voto finale. 100% - valutazione materiale prodotto durante esercitazioni: max 3 punti aggiuntivi al voto dello scritto orale: opzionale per chi ha superato lo scritto con votazione >=27 the oral examination about Car Body Design part is a discussion about the concepts illustrated in the lectures. the score of oral examination can go from -5 to +5 marks. Parte: Aerodynamics (Massai) Esame: orale the following elements take part of the oral evaluation - discussion about results obtained during CFD laboratory sessions - analysis of the aerodynamics of a current car of your choice in a assigned range - discussion about main principles of car body aerodynamics - graphical capability in the technical sketch of vehicle aerodynamics concepts According to the number of class and exercise hours the two parts of the course are composed in the following percentages to form the final score. Car Body Design = 60% Aerodynamics=40% |
Orario delle lezioni |
Statistiche superamento esami |
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