OVERVIEW

The module aims to illustrate methods for solving classic structural mechanical problems that are fundamental for the advanced design of mechanical components and systems. Essentially, the module delves deeper into issues addressed during the Bachelor's program concerning solid mechanics and machine elements involving geometrically complex components and non-linear loading situations, also through the use of numerical methods.

AIMS AND CONTENT

LEARNING OUTCOMES

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

AIMS AND LEARNING OUTCOMES

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 apply 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).

TEACHING METHODS

Contextual lectures and worked examples held by the teacher.

Students who have valid certification of physical or learning disabilities on file with the University and who wish to discuss possible accommodations or other circumstances regarding lectures, coursework and exams, should speak both with Professor Federico Scarpa (federico.scarpa@unige.it), the Polytechnic School's disability liaison.

SYLLABUS/CONTENT

Part 1 - Fundamentals of mechanic structural design under static loads. Recalls on :
a) Solid Mechanics and Structural Mechanics.

b) Elementary one-dimensional 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 high-temperature creep. Coefficients of safety against structural failure.
- Physical nonlinearities : plasticity. Examples of elastic-plastic 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. Post-processing 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 elastic fracture mechanics.

Part 4 - Multiaxial fatigue and fatigue crack propagation.

RECOMMENDED READING/BIBLIOGRAPHY

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)

TEACHERS AND EXAM BOARD

LESSONS

LESSONS START

https://corsi.unige.it/en/corsi/11959/studenti-orario

Class schedule

The timetable for this course is available here: Portale EasyAcademy

EXAMS

EXAM DESCRIPTION

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 hand-calculators and consulting every text) and then the board (in the second part of the examination, without using hand-calculators and without consultation of texts).

ASSESSMENT METHODS

The written exam will assess the competence in using the design tools proposed for the correct sizing of the mechanical components and systems covered in the course. The oral exam will evaluate the clarity in presenting the topics discussed, and thus the in-depth understanding of the methods and tools proposed during the course, with particular attention to their limitations and fields of application.