CODE  60299 

ACADEMIC YEAR  2021/2022 
CREDITS 

SCIENTIFIC DISCIPLINARY SECTOR  INGIND/14 
LANGUAGE  Italian 
TEACHING LOCATION 

SEMESTER  2° Semester 
MODULES  This unit is a module of: 
TEACHING MATERIALS  AULAWEB 
To present criteria for the design of mechanical components and machine parts subjected to static, dynamic, and fatigue loadings. Describe analytical models and numerical methods for the structural analysis of mechanical components and systems
The course aims to:
1) present and apply the criteria for the mechanical design of components and machine parts subjected to static, dynamic and fatigue loads ;
2) describe the classical analytical models used for the structural analysis, and aplly them for simple design calculations;
3) introduce the fundamentals of numerical finite element technique for 2D and 3D structures composed of discrete elements (trusses and beams).
Contextual lectures and worked examples held by the titular teacher
Part 1  Fundamentals of mechanic structural design under static loads. Recalls on :
a) Solid Mechanics and Structural Mechanics.
b) Elementary onedimensional structures (beams and rods).
c) Special problems of solid mechanics : plane stress / strain problems and axisymmetric problems.
d) Rotating disks and cylindrical shells.
e) Causes of stress. Concentrated and distributed forces (surface and volume forces). Initial deformation (thermal and interference). Causes of collapse. Failure due to overcoming of static strength, fatigue, and crash. Failure due to elastic instability and hightemperature creep. Coefficients of safety against structural failure.
 Physical nonlinearities : plasticity. Examples of elasticplastic calculations : plastic hinge.
 Geometric nonlinearitie: large displacement. Contact nonlinearities: unilateral constraints.
Part 2  Fundamentals of the finite element method. Matrix methods for the analysis of discrete element structures . Stiffness matrix. Vectors of forces and nodal displacements. Assembly, constraint specification and solution of equations. Postprocessing of results. Shape functions and stiffness matrix for a generic finite element. Convergence of the solution. Tension matrix and deformation matrix. Criteria for the discretization of a solid into 2D / 3D finite elements. Plane triangular element with three nodes . Axisymmetric triangular element with three nodes .
Part 3  Linear approach to the mechanical dynamic structural design . The simple oscillator (recalls). Examples of dynamic systems with 1 or 2 degrees of freedom. Overview of distributed parameter dynamic systems . Axial , bending and torsional vibrations. Torsional bipendulum. Torsional tripendulum.
Part 4  Rotor Dynamics : the Jeffcott rotor. Critical speeds. Causes of damping in a turbine rotor. Examples of modeling and examples of dynamic calculations of rotating systems. Inertia redution in a torque crank rod. Inertia and elasticity reduction of a system rotating on two axes to a torsional bi/tripendulum
Part 5  Notes on the structural design of gas and steam turbines. Static calculation (with the ANSYS code) of a turbine rotor ..Modal analysis of a lowpressure blade for a steam turbine. Materials for gas turbines subject to creep. Seminars Ansaldo Energia of mechanical design of steam turbines.
Part 6  Theory of thin plates. Uniformly deflected circular plate. Axisymmetric plates
Lecture notes. Any text in Machine design (e.g. J.E. Shigley, C.R. Mischke, R.G. Budynas : “Progetto e costruzione di macchine” , McGraw Hill)
PIETRO FANGHELLA (President)
MASSIMILIANO AVALLE
LUCA BRUZZONE
MARGHERITA MONTI
LUDOVICO MUSENICH
LINDA RAVAZZANO
ROBERTO RAZZOLI
ALESSANDRO REBORA
ALESSANDRO STAGNI
MATTEO VEROTTI
FLAVIA LIBONATI (President Substitute)
Oral exam on theoretical and application items presented during lectures, dealing with simple numerical exercises to be performed on sheets of paper (in the first part of the
examination, using handcalculators and consulting every text) and then the board (in the second part of the examination, without using handcalculators and without consultation of texts).
Date  Time  Location  Type  Notes 

18/01/2022  09:30  GENOVA  Scritto  
08/02/2022  09:30  GENOVA  Scritto  
07/06/2022  09:30  GENOVA  Scritto  
30/06/2022  09:30  GENOVA  Scritto  
06/09/2022  09:30  GENOVA  Scritto 
Prerequisites :
80137 Mechanics modulus