85817 - Chassis and Body Design and Manufacturing

Academic Year 2021/2022

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.

WELDING JOINTS

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

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.

FEA laboratory with commercial softwares

Introduction and solution of linear static problems
Numerical modeling of threaded joints, 1d and 3d approaches.
Numerical modeling of welding joints.
Numerical modeling of adhesively bonded joints.
Solution of nonlinear problems (large displacements, nonlinear materials, contact).

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

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.

D. G. Pavlou, Essentials of the Finite Element Method: For Mechanical and Structural Engineers, 2015 Ed. Elsevier Academic Press.

S. Timoshenko, J. N. Goodier, Theory of Elasticity, 1951 Ed. McGraw-Hill.

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.

As concerns the teaching methods of this course unit, all students must attend Module 1, 2 [https://www.unibo.it/en/services-and-opportunities/health-and-assistance/health-and-safety/online-course-on-health-and-safety-in-study-and-internship-areas] on Health and Safety online.

Assessment methods

1) 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.

2) 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.