Knowledge: Knowledge of Vehicle postural ergonomics, accessibility, direct and indirect visibility, structure solutions adopted for the of passenger cars and light duty vehicles with conventional, electric and hybrid powertrain, methods for the analysis of the stress and strain. Knowledge of the loads (external and internal) during operation and during crash events. Sources of noise and vibration, behavior of the vehicle structure under dynamic excitation. Human sensitivity to noise and vibration. Analysis of the aerodynamic and aero-acoustic field, simulation techniques using computational fluid dynamics and wind tunnel experimental measurements. Injury criteria, impact testing procedures following regulatory and rating procedures, structural solutions for crash energy dissipation. Restraint systems. Skills: Capability to define the vehicle packaging considering the occupants ergonomics, visibility, accessibility and structural constraints. Capability to setup a vehicle structure and analyze its main structural performances in terms of stiffness (torsional and bending), dynamic responses such as mode shapes, natural frequencies and frequency response functions. Analyze by finite element tools the response of the vehicle structure under the effect of the dynamic loads acting on it. Optimize the aerodynamic shape to reduce the drag and insure the functionality of the cooling and air conditioning system. Understand the main constraints coming from crashworthiness regulations and design or specify the subsystems dedicated to insure an adequate level of passive safety.

Motor Vehicle Design, Machine Design, Applied Mechanics, Fundamentals of Strength of Materials. Fluid mechanics, Numerical Modelling.

1 - Introduction (1,5 h) Prerequistes and functions of the motor vehicle from the bodywork point of view. 2 – Vehicle packaging (9) Ergonomics and posture Percentiles and manikins for packaging Main constraint to interior packaging coming from vehicle body structure: wheel arches, tunnel, firewall, pedals, underbody. Seating position and seat comfort Accessibility to the vehicle and to commands Direct and indirect visibility 3 – Structure (10,5 h) General vehicle structure architecture for different vehicle types and with conventional, hybrid and electric powertrains. Reference load cases: loads coming from manoeuvres and obstacles, internal loads due to powertrain, suspensions and safety belts; loads on bodywork surface. Simplified model of the car structure when subject to internal and external loads. Structural surface method to analyze torsional and flexural behavior of open and closed chassis architectures. Structural analysis of monocoque configuration: underbody types and evaluation of their torsional stiffness. H, I, X, ladder frame analysis. Influence of open or closed cross section beams. 4 – Noise and vibration (10,5 h) Vibration and noise sources from powertrain, wheels, aerodynamic noise. Introduction to the dynamic behavior of the bodywork and modal analysis. Vibration response and attenuation. 5 – Passive safety (7,5 h) Injury criteria, HIC, tibia index, neck, viscous criteria. Role of restraint system and main parameters affecting the occupants accelerations during a crash. Crashes of small intensity: Insurance tests, tests on bumpers. High speed crash tests for homologation and rating. 6 - Introduction to vehicle aerodynamics (6 h) Equations governing uncompressible fluids. Limited laminar and turbulent layers Aerodynamic resistance from friction and pressure. 7 - Aerodynamic resistance (10,5h) Contributions to the aerodynamic resistance. Flow structure around squat bodies. Effect on consumption and performance. 8 - Aerodynamic effects on vehicle functionality (7,5h) Aerodynamic noise. Stability with lateral wind. Engine cooling Brake cooling. Soiling and dispersion of exhaust fumes. 9 - Experimental aerodynamics (7,5 h) Automobile wind tunnels. Tests on scaled models. Measurement of the aerodynamic and aerodynamic forces and moments. Techniques for measuring the fluid-dynamic variables (pressure, speed, heat cables, LDV, PIV). Measurement of aerodynamic noise. Measurement of air flows under the bonnet Road tests. 10 - Computational aerodynamics (9 h) Numeric methods for equations of fluid motion. Calculations grids and their creations based on CAD geometry. Turbulence models. Boundary conditions. Elaborations and visualization of the results.

The course is organised as follows: Lessons in classroom: (51 hours) Exercises in classroom: the exercises are organized in projects about the following topics: vehicle packaging, torsional stiffness evaluation of frames, modal analysis. Exercises in laboratory: CFD analyses will be performed in the Information Technology laboratories (23 hours). Visits: Wind Tunnel experimental facility, experimental facility for passive safety assessments (6 hours) The work done by the students during the exercises will be documented by exercise reports. These reports are prepared in teams of 3-4 students each, they have to be uploaded on the Teaching Portal at least one week before the exam. In a.y. 2020/21 the lessons and exercises will be held in the form of virtual classooms by means of the BBB platform. All virtual classrooms will be recorded and made available on Portale della Didattica. A in the presence exercise session will be made available each week for a number of students according to the safety regulations and on the availability of classrooms.

The teaching material needed for preparing the exam is all made available on Portale della Didattica. It includes slides, notes, and recorded virtual classrooms. Further reading for gaining a deeper insight can be found in the following literature: L. Morello, L. Rosti Rossini, G. Pia, A. Tonoli, “The Automotive Body”, Voll, I and II, Springer, 2011. 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.

Exam: Computer-based written test using the PoliTo platform; Group project;

Expected learning outcomes Knowledge and capability to define the vehicle packaging considering the occupants ergonomics, visibility, accessibility and structural constraints. Knowledge of the main a vehicle structure architectures of passenger cars and their main structural performances. Capability to analyze the load distribution in frames and box structures under the effect of bending and torsional loads. Knowledge about the dynamic responses and human sensitivity to vibration, modal analysis and modal reduction, natural frequencies and frequency response functions. Optimize the aerodynamic shape to reduce the drag and insure the functionality of the cooling and air conditioning system. Wind tunnel testing and measurement techniques to evaluate different aerodynamic performances. Methodologies for the analysis of the aerodynamic performances by means of Computational Fluid Dynamic tools. Injury criteria, impact testing procedures following regulatory and rating procedures, structural solutions for crash energy dissipation and estimation of their characteristics. Role of the restraint systems. The aim of the exam is to verify if and in what measure the learning outcomes are consistent with the expected ones as described above. The exam is conceived to verify the knowledge acquired in the field of the vehicle packaging and visibility, vehicle structure, noise and vibration, aerodynamics, aerodynamic testing and computational fluid dynamics. The exam is also aimed to verify the capability of the student to elaborate the given knowledge and elaborate it to obtain results and allow to take personal decisions in the field of vehicle body design. This is obtained by the evaluation of the exercise reports prepared during the semester. Additionally one part of the written exam is devoted to numerical exercises. Exam rules and procedure The Motor Vehicle Design exam consists of 30 multiple choice questions and 8 numerical exercises. Each multiple-choice question has just one correct answer. The numerical exercises require to solve a numerical problem similar to those shown during the exercise lessons. The time to complete the exam is 2 hours. During the exam it is possible to use just a simple scientific calculator, pen and paper or the calculator available in Respondus interface. Exchange information among students is not permitted by any means. Use of multimedia devices such as cell phone, tablet, pc, smart watch is not allowed. Use of any written material such as notes, textbooks is not allowed. Scoring: The total exam score is composed by the evaluation of the written exam, the exercise reports and an optional oral as follows Written exam The written exam is composed of multiple choice questions, numerical exercises, and exercise reports 30 m.c.questions Correct answer: + 1 point No answer: 0 points Wrong answer: - 1/2 points 8 numerical exercises Correct answer: +2 points No or wrong answer: 0 points The total score of the multiple-choice questions and the numerical exercises is rescaled linearly to 32/30. The four exercise reports prepared during the semester are evaluated with a score from 0 to 3 points that are added to the score of the multiple-choice questions and the numerical exercises (after rescaling). The exercise reports have to be uploaded in pdf form on the “elaborati” section of the Portale della Didattica at least one week before the written exam. Score of written exam=(score of multiple choice + score of numerical exercise)*32/46 + score of exercise reports. The exam is overcome successfully for scores higher than 18/30. The scores are uploaded on Portale della Didattica within a week from the written exam. The corrected written exam can be viewed during a dedicated session that is scheduled after the publication of the scores. The date is noticed by means of the Portale della Didattica. Optional oral examinations is possible just for scores of the written exam higher or equal to 27/30 or in cases left to the teacher's decision, such as an unclear result of the written. The oral examination consists in a number of at least three questions covering the course program for a further assessment of the expected learning outcomes. The student will be asked to answer giving priority to quantitative arguments, graphical representations, and analytical reasoning. The oral examination can lead to an increment as well as a reduction of the score obtained in the written.

Exam: Written test; Optional oral exam; Individual essay;

Expected learning outcomes Knowledge of the concepts and capability to define the vehicle packaging considering the occupants ergonomics, visibility, accessibility and structural constraints. Knowledge of the main a vehicle structure architectures of passenger cars and their main structural performances. Capability to analyze the load distribution in frames and box structures under the effect of bending and torsional loads. Knowledge about the dynamic responses and human sensitivity to vibration, modal analysis and modal reduction, natural frequencies and frequency response functions. Optimize the aerodynamic shape to reduce the drag and insure the functionality of the cooling and air conditioning system. Wind tunnel testing and measurement techniques to evaluate different aerodynamic performances. Methodologies for the analysis of the aerodynamic performances by means of Computational Fluid Dynamic tools. Injury criteria, impact testing procedures following regulatory and rating procedures, structural solutions for crash energy dissipation and estimation of their characteristics. Role of the restraint systems. The aim of the exam is to verify if and in what measure the learning outcomes are consistent with the expected ones as described above. The exam is conceived to verify the knowledge acquired in the field of the vehicle packaging and visibility, vehicle structure, noise and vibration, aerodynamics, aerodynamic testing and computational fluid dynamics. The exam is also aimed to verify the capability of the student to elaborate the given knowledge and elaborate it to obtain results and allow to take personal decisions in the field of vehicle body design. This is obtained by the evaluation of the exercise reports prepared during the semester. Additionally one part of the written exam is devoted to numerical exercises. Exam rules and procedure The Motor Vehicle Design exam consists of 30 multiple choice questions and 8 numerical exercises. Each multiple-choice question has just one correct answer. The numerical exercises require to solve a numerical problem similar to those shown during the exercise lessons. The time to complete the exam is 2 hours. During the exam it is possible to use just a simple scientific calculator, pen and paper or the calculator available in Respondus interface. Exchange information among students is not permitted by any means. Use of multimedia devices such as cell phone, tablet, pc, smart watch is not allowed. Use of any written material such as notes, textbooks is not allowed. Scoring: The total exam score is composed by the evaluation of the written exam, the exercise reports and an optional oral as follows Written exam The written exam is composed of multiple choice questions, numerical exercises, and exercise reports 30 m.c.questions Correct answer: + 1 point No answer: 0 points Wrong answer: - 1/2 points 8 numerical exercises Correct answer: +2 points No or wrong answer: 0 points The total score of the multiple-choice questions and the numerical exercises is rescaled linearly to 32/30. The four exercise reports prepared during the semester are evaluated with a score from 0 to 3 points that are added to the score of the multiple-choice questions and the numerical exercises (after rescaling). The exercise reports have to be uploaded in pdf form on the “elaborati” section of the Portale della Didattica at least one week before the written exam. Score of written exam=(score of multiple choice + score of numerical exercise)*32/46 + score of exercise reports. The exam is overcome successfully for scores higher than 18/30. The scores are uploaded on Portale della Didattica within a week from the written exam. The corrected written exam can be viewed during a dedicated session that is scheduled after the publication of the scores. The date is noticed by means of the Portale della Didattica. Optional oral examinations is possible just for scores of the written exam higher or equal to 27/30 or in cases left to the teacher's decision, such as an unclear result of the written. The oral examination consists in a number of at least three questions covering the course program for a further assessment of the expected learning outcomes. The student will be asked to answer giving priority to quantitative arguments, graphical representations, and analytical reasoning. The oral examination can lead to an increment as well as a reduction of the score obtained in the written.