Dinamica del Veicolo (M. Guiggiani)
Meccanica dell'autoveicolo (G. Genta)
Tire and Vehicle Dynamics (H.B. Pacejka)
Lezioni di meccanica del veicolo (A. Rindi)
Learning Objectives
cc1: In-depth knowledge and understanding of the theoretical-scientific aspects of engineering, with a specific reference to mechanical engineering, in which students are able to identify, formulate and solve, even in an innovative way, complex and/or interdisciplinary problems. The ability to understand a multidisciplinary context in the engineering field and to work with a problem solving approach.
cc8: Knowledge and understanding of the land-based vehicle sector by deepening the structural aspects of the various vehicle types. Knowledge and understanding of electrical machinery and related traction power supply systems. Knowledge and understanding of the structural and thermo-fluiddynamic aspects of internal combustion engines.
ca1: Applying knowledge and understanding related to problem identification and formulation of solutions, in the field of mechanical engineering, to set up, design, implement and verify systems and apparatus, even of high functional complexity, taking into account the implications related to environmental, economic and ethical aspects, employing well established methods.
Prerequisites
The lecturer assumes as acquired by the students the knowledge and competencies in Theory of Mechanics and Machines.
Teaching Methods
De visu lectures.
Type of Assessment
Oral exam with 3 or 4 questions on theoretical and practical issues
Course program
The course deals with the main relevant aspects of vehicle dynamics both on road and on railway; more in detail it present the basic topics to understand and to implement the behavior of:
- contact forces generation between road-tire and between track and wheel
- longitudinal dynamics (e.g. vehicle performances, max sped, max acceleration.; braking performance)
- lateral dynamics (e.g. oversteering and understeering; running stability )
- vertical dynamic (e.g. comfort; running safety).
Road autovehicle
1. Tire-road Contact
Model of Coulomb
Brush model for longitudinal and lateral forces
Magic formulae; longitudinal, lateral and combined forces;
Influence on Adhesion curves of the vertical load, camber angle, speed...
2. Aerodynamic actions
3. Dynamics Longitudinal
Braking: Transfer load. Proportioning Braking System assisted braking systems (ABS, ESP ....)
Power curves, torque and specific consumption of an motor
Model 1 DOF model with Tire-road Coulomb model
Model 3-DOF model with Tire-road Pacejka model.
Vehicle Performance: Maximum gradeability, maximum speed on a level road, full throttle on a level road.
Choice of gear ratios
4. Lateral Dynamic
steering kinematics
Steering dynamic model 3 DOF; General equations of motion,
Directional stability: the linearized equations of motion; derived stability;
steering response; response to forces and moments.
5.Vertical Dynamics
Types of suspension
Comfort: 1 DOF and 2 DOF (quarter-model) models
Influence of the suspended masses
Rail vehicle
wheel-rail contact
Parameters that affect the coefficient of adhesion
Normal problem (Hertz theory)
Tangential Problem (linear theory of Kalker, theory of Johnson-Vermeulen, heuristic theories)
Track forces. Safety against derailment: wheel flange climbing, vehicle turnover, rail turnover. Wheel and rail wear. Ride comfort. Vehicle gauging.