15615 - Machine Design

Learning outcomes

The outcomes of the course are to provide the basic knowledge, the methods and the tools useful for the correct definition of the mechanical design activities. At the end of the course the students will be able to reproduce the representation of a simple mechanical system, to define the relationship between the elements, to calculate the constraints, to draw the stress diagrams and to compute the maximum tensile state of the components. Furthermore they will be able to verify the fatigue life of simple mechanical components and to calculate the strength of some basic bolted and welted structures. Finally they will be able to select the most appropriate rolling bearings to be positioned as constraints of shafts, pins and axes.

Course contents

Introduction to the study and to the analysis of a mechanical system.

Function analysis of a product; the kinematics and dynamic representation of a simple mechanical system and the relationships between the machine elements.

The rigid body equilibrium.

Work and power. Motion and energy transmission between the machine elements. Morphologic characteristics and the load analysis of the mechanical systems. Structural models and tensile state analysis. Stress concentration factors. Residual stresses. The normal stress. The bending stress. The shear stress. The torsion stress. The failure of materials under static loads. The equivalent uniaxial stress in case of static load.

Fatigue of metals. The S-N (Wlöer) curves and the Haigh diagrams. The surface, gradient, dimension and load effects on the fatigue strength. The equivalent uniaxial stress in case of dynamic load. The medium stress effects on the fatigue strength.

Numerical Structural analysis

Mechanical Joints.

Thick axisimmetric structures.

Fundamentals of bolted and welded structures.

Bearings.

Strain energy.

Buckling.

Readings/Bibliography

Shigley
De Paulis-Manfredi
Giovannozzi
Spotts
Dal Re

Cesari

Teaching methods

The lectures concern the fundamentals problems of the mechanical design of products and systems. The practising are collective and concern the application and practical solutions of theoretical problems proposed during the lectures.

Assessment methods

After a written part the exam is oral, based on the discussion of homeworks.

Teaching tools

PC projector,  blackboard

Office hours

See the website of Giangiacomo Minak