Machines Design - a.y. 2016/2017
Period (Year/Semester): III/II
Required/expected prior knowledge: Building Science
Lecturers: Luca Esposito
Scope of the course is to provide the fundamental design criteria for the assessment of mechanical components subjected to static, dynamic, high and low temperature loading conditions with particular attention to the mechanisms responsible for failure.
Tables of contents:
Introduction to failure mechanisms in metals and alloys. Static design of simple machinery components. Notch and geometric effecton the structural assessment. High cycle fatigue: micromechanisms and fundamentals, random fatigue, multi-axial fatigue, load spectra and damage rules. Mean stress and othereffects on fatigue strength.Low cycle fatigue: mechanisms, cyclic hardening and softening behavior, strain diagram. Neuber rule for notched components. Brittle Fracture: cleavage, elastic fracture mechanics, energetic vs stress based approach, K dominance, design of components with flaw. Fatigue with cracks: Paris law. Component design: axisymmetric solids (cylinders, vessels, rotating disks), pressure vessel design, bolted joints, fundamentals of springs design; brakes and clutches.High temperature design: creep, mechanisms, Ashby diagram, dislocation based modeling. Acceleration methods, Larson-Miller law.
Classroom lectures and exercises.
Textbooks and learning aids:
Richard G. Budynas, J. Keith Nisbett “Shigley - Progetto e costruzione di macchine”, McGraw-Hill, III ed.;
J. A. Collins “Failure of materials in mechanical design”; Feodosev“Resistenza dei materiali”;
Lecture notes provided by the teacher.
Assessment will be written and oral. In itinere tests.