85817 - Chassis and Body Design and Manufacturing

Academic Year 2020/2021

Learning outcomes

The outcomes of the course are to provide the advanced knowledge, the methods and the tools useful for the correct design and verification of the chassis components. The students will learn how to tackle the design of a motorbike frame by means of both analytical and numerical FEA tools. A special focus will be put on joining methods suitable for lightweight structures (adhesives, bolts, welds). The design of some key components, such as suspension elements, will be examined in depth. At the end of the course, the students will be able to select the most appropriate structural solutions based on the product mission, taking into account both the performance targets (e.g. stiffness, weight) and the expected failure modes the product must be designed against (e.g. fatigue, wear), in the framework of the requirements set by the relevant International Standards.

Course contents

INTRODUCTION


Statically indeterminate structures: force method and displacement method. Strain energy methods. Rotating-node and translating-node frames.


THREADED JOINTS


Screws: static and fatigue dimensioning and assessment. Calculation methods according to Eurocode 3 and VDI 2230. Axial preload and tightening torque. Determination of the coefficients of friction according to ISO 16047. Friction coefficients requirements according to the automotive field normative. How to account for data scatter in dimensioning threaded joints. Load introduction factor. Prying load. Residual shank torsion. Self loosening and self-relaxation issues.


Numerical modeling of threaded joints, 1d and 3d approaches.


WELDED JOINTS


Static and fatigue dimensioning and assessment.Failure criteria. Calculation method according to Eurocode 3 (steel) and Eurocode 9 (aluminium).


Numerical modeling of welded joints.


ADHESIVELY BONDED JOINTS


Static and fatigue dimensioning and assessment. Single-lap joints: Volkersen and Goland&Reissner theories. Cylindrical joints: dimensioning according to the Loctite method. Hybrid joints: interference fit plus adhesive.


Numerical modeling of adhesively bonded joints.


MECHANICAL SPRINGS


Flat and leaf springs. Helical compression, extension and torsion springs. Calculation methods according to EN 13906. Belleville and ring springs (basics). Elastomeric springs.


EXPERIMENTAL STRESS ANALYSIS


Strain gauges: materials, measuring circuits, data acquisition. The gage factor. Single grid strain gauges and rosettes. Determining residual stresses by the hole-drilling strain gauge method.


TUTORIALS AND CASE STUDIES

Readings/Bibliography

Lecture slides: these will be made available on the internet.


A. M. Wahl, Mechanical Springs, 2nd Ed. Mc Graw Hill Book Company.


A. Freddi, G. Olmi, L. Cristofolini, Experimental Stress Analysis for Materials and Structures: Stress Analysis Models for Developing Design Methodologies, Springer.


B. J. Mac Donald, Practical Stress Analysis with Finite Elements (2nd Edition), Ed. Glasnevin

 

G. Genta, L. Morello, The automotive Chassis, Springer.

Teaching methods

The course content will be entirely covered by the lectures. Lectures are supported by many practical exercises, aimed at guiding the students towards the solution of practical problems, based on the tools acquired during the theoretical lectures.

Assessment methods

Discussion of the group project: each student must attend the final presentation of the group project. Discussion (with a positive mark) of the group project is a prerequisite for accessing the following step of the examination

Individual oral discussion: dealing with the group project and, more generally, the topics covered by the course.

Teaching tools

Video projector, Tablet with hand-writing function, Computer Lab.

Office hours

See the website of Massimiliano De Agostinis

SDGs

Industry, innovation and infrastructure Climate Action

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.