The module of Structural Mechanics aims at providing students with the fundamentals to understand, analyze, and critically assess the structural behavior of key components in power plants during service. The Structural Mechanics module covers the following topics: analytical models describing the mechanical behavior of structural materials, static failure mechanisms, and fatigue failure — including high-cycle fatigue, low-cycle fatigue, and thermomechanical fatigue — affecting both materials and components. Design and verification practices for pressure vessels will also be addressed, following both analytical methods and standards.

The Structural Mechanics module aims to provide students with the knowledge required to understand the failure behavior of structural components under both static and cyclic loading conditions. It also enables them to perform the main calculations involved in the structural design and verification of pressure vessels and related components, in accordance with the technical guidelines defined by applicable standards. By the end of the module, students are expected to be able to carry out preliminary design and verification of key components used in power plants.

The Structural Mechanics module requires prior knowledge of fundamental topics in Strength of Materials. In particular, students are expected to be familiar with the stress state of beams in the elastic range, including axial, bending, and torsional loading conditions, as well as with the basic principles of stress and strain theory and the mechanical properties of metallic materials.

The Structural Mechanics module aims to provide an overview of the following topics: 3D stress and strain status. Stress vector and tensor. Principal stresses and principal directions. Stress status invariants. Hydrostatic and deviatoric stress status. Mohr circles for stress. Main loading conditions for beams. Deformation kinematics. Strain vector and tensor. Principal strains. Relation between stress and strain: Hooke’s law. Static resistance. Tensile test. Brittle and ductile materials. Failure criteria for brittle and ductile materials. Static safety factor against static failure. Effect of temperature on mechanical properties of metallic materials. Creep. Notch effect and stress intensity factor. Notch effect in static failure. Fatigue resistance. Phenomena related to fatigue and characteristic parameters. Whoeler (SN) diagrams: fatigue limit. SN material diagram estimation. Influence of mean stress: Haigh diagram. Influence of load, of dimensions, of surface finish and of notch. Component fatigue limit. Haigh diagram and SN component curves. Fatigue safety factor. Fatigue with variable amplitude stresses. Multiaxial fatigue. Cyclic and thermo-mechanic cyclic behavior: low-cycle fatigue, isothermal and thermomechanical. Parameters describing low cycle fatigue behavior and corresponding constitutive models. Parameters describing thermomechanical fatigue behavior and corresponding constitutive models. Damage models: classification, uniaxial models, multiaxial models. Residual life estimation. Case studies. Pressure vessels. Definition of the problem, differential equilibrium equation and its solution. Determination of stress status generated by internal and external pressure and by thermal gradient. Pipings. Axialsymmetric plates: axialsimmetric shells. Edge effect. Bolted joints, design and verification.

The theoretical part of the course will cover the required topics through the development of analytical models and equations, as well as the discussion of case studies. Classroom tutorials will focus on formulating and solving practical problems related to the topics covered in the lectures, with the aim of deepening the understanding of theoretical concepts and providing students with insight into the role and influence of key parameters in structural analysis and design. A 1.5 hourse laboratory session will also be held, during which strains on a pressure vessel will be measured and compared with analytical predictions.

Students are warmly invited to attend both theory lectures and tutorials to better understand the content of the slides shared by the professor on the web teaching portal. Suggested books are: • Shigley's mechanical engineering design, Richard G. Budynas, McGraw-Hill Education • A textbook of machine design, R.S. Khurmi J.K. Gupta, McGraw-Hill Education • F. Cesari, D. Martini, I recipienti in pressione, Pitagora Editrice Bologna, 2012.

Slides; Esercizi; Esercizi risolti; Esercitazioni di laboratorio; Materiale multimediale ;

Modalità di esame: Prova scritta (in aula); Prova orale obbligatoria; Prova pratica di laboratorio; Elaborato scritto prodotto in gruppo;

Exam: Written test; Compulsory oral exam; Practical lab skills test; Group essay;

... The exam consists of two parts: a written test (numerical exercises) and an oral test (theory). The written test lasts 1.5 hours and includes two exercises, one for each module of the course. The type and complexity of the exercises are similar to those covered during class tutorials. Consultation of notes or any external material is not permitted during the written test, except for a single A3 sheet prepared by the student, containing formulas. The oral test will be scheduled according to a calendar published within one day after the written exam. It consists of one question on theoretical topics. To be admitted to the oral test, the student must obtain a score of at least 18/30 in both written exercises. During the oral test, students are required to bring a printed report of the experimental lab activity on strain measurement in pressure vessels. This report will be discussed with the professor, and up to 2 bonus points may be awarded and added to the average score (written + oral) of the Structural Mechanics module. At the end of the oral test, a score will be assigned for each module, based on the results of both the written and oral tests. The exam is considered passed only if the student obtains a grade of at least 18/30 in both the written and the oral tests. The final grade is calculated as the average of the scores obtained in the two modules. The written test is intended to assess the ability to solve practical problems involving material properties, failure mechanisms, and load-bearing models, reflecting real-world applications. The oral test evaluates the student's ability to reason beyond standard exercises, particularly in handling analytical models describing the behavior of materials and structures under operating conditions. This includes both the understanding of model assumptions and their application to case studies.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.