Unit MECHANICS OF THE VEHICLE

Course
Mechanical engineering
Study-unit Code
70146108
Curriculum
Costruzioni
Teacher
Giordano Franceschini
Teachers
  • Giordano Franceschini
Hours
  • 64 ore - Giordano Franceschini
CFU
8
Course Regulation
Coorte 2021
Offered
2022/23
Learning activities
Caratterizzante
Area
Ingegneria meccanica
Academic discipline
ING-IND/13
Type of study-unit
Obbligatorio (Required)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
Italian
Contents
The course introduces some models, of calculation and simulation, which describe the behavior of the vehicle on road. Numerous models concern the sport vehicle, as it is more easily schematized and with a simpler objective function than the road vehicle.
Some of the models themselves were developed by the same teacher as part of his research activity.
The results of the models are taken as the basis of design criteria.
Some aids such as telemetry and simulation are also described and used.
Reference texts
Handouts and supports provided by the teacher, with indication of the bibliographical references to some reference texts for the various topics.
Educational objectives
Knowledge of the main physical models associated with vehicle mechanics and some design criteria.
Prerequisites
Good knowledge of: Physics 1, Rational Mechanics, Applied Mechanics is considered
Teaching methods
Frontal lessons and computer exercises.
Workshop - laboratory visits are scheduled to view some vehicles or parts of them.
For the exact description of some phenomena the use of videos is foreseen.
Other information
none
Learning verification modality
Oral final exam or written test on course exercises.
Extended program
Presentation of the course: and general information on the vehicle models: TGiro, Sosp, Rollio
Tgiro model of a given circuit. Lap time calculation criteria.
Chassis model: Reference system and vertical loads. Weight distribution of a vehicle.
Tgiro model of the chassis: Aerodynamic loads; the inertial effects of acceleration and braking. Load transfer concept.
Centrifugal effects. The load transfers obtained with the equivalent model of the vehicle at the roll in the case of sn infinitely rigid chassis.
Extension of the model to the case of a frame that is not infinitely rigid.
Tire adherence model: traction ellipse criterion.
Model Tgiro calculation of the maximum CONSTANT speed of the curve.
Tgiro model of the engine and transmission.
Tgiro model: algorithms for calculating maximum acceleration and braking in a straight line.
Tgiro model: summary and calculation of the minimum lap time on a given circuit.
Comparison of setting parameters with the Tgiro model.
The tire: grip and drift. Radial tire model. Regulations relating to rim and tire measurements.
Influence of tire drift on vehicle cornering behavior: understeer and oversteer.
The suspension of the vehicle. Springs and shock absorbers. Compression and extension.
Study of vehicle suspension from a geometric point of view. Setup parameters and angles. 'Recovery' laws of the structure parameters.
The SOSP simulation model for double wishbone suspensions. Discussion on the usefulness of the iterative model compared to other criteria.
Modeling of a single suspension with SOSP: concept of rotating wishbone. Recall on the transformation matrix.
Extrapolation of the main set-up parameters with the SOSP program. Preparation of recovery laws. Rocker ratio concept.
Processing with SOSP and criteria.
The roll center approximation and its study with the SOSP system.
Steering simulation with SOSP and criticism of the Ackermann steering system.
Steering simulation: caster and king pin angles and their effects. The bump steer.
Introduction to the roll model: extension of the equivalent model studied. Anti-roll bar concept and its equivalent scheme.
The vehicle setup criteria using the roll model.
Discussion on the limitation to the adjustability of the vehicle in the case of a frame which is not infinitely rigid.
Evaluations relating to the torsional rigidity of the vehicle with specific cases and test comments.
Telemetry and data acquisition on board. Some examples of telemetry tracks and interpretation criteria drawn from sports experiences.
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