ELEMENTS OF STRUCTURES IN INNOVATIVE MATERIALS
cod. 1011123

Academic year 2024/25
2° year of course - First semester
Professor
Gianni ROYER CARFAGNI
Academic discipline
Scienza delle costruzioni (ICAR/08)
Field
A scelta dello studente
Type of training activity
Student's choice
48 hours
of face-to-face activities
6 credits
hub:
course unit
in ITALIAN

Learning objectives

The course aims to provide students with fundamental skills related to structures made with innovative materials, with a particular focus on the mechanical, physical, and sustainability characteristics of these materials. By the end of the course, students will be able to:

Understand and analyze the properties of innovative materials: gain in-depth knowledge of new structural materials (e.g., composite materials, carbon-based materials, high-performance ceramics, rubbers, and polymeric materials) and their engineering applications.

Apply structural design principles: develop the skills to design and optimize innovative structures, considering the mechanical and physical properties of the materials used as well as relevant regulations.

Evaluate sustainability and efficiency: understand the role of innovative materials in sustainable design, taking into account energy efficiency, environmental impact, and structural durability.

Experiment with material use: gain the ability to use laboratory tools and techniques to test and characterize innovative materials and interpret the data obtained to improve structural performance.

Design innovative solutions: develop problem-solving skills to address complex structural issues using innovative materials, assessing design alternatives and optimizing solutions based on technical and economic requirements.

Collaborate in multidisciplinary contexts: acquire communication and teamwork skills, contributing to the analysis, design, and implementation of structural projects using innovative materials in professional and multidisciplinary settings.

These objectives prepare students to harness the potential of new materials in advanced fields, such as the automotive and aerospace industries.

Prerequisites

Basic knowledge of structural mechanics. The course "Scienza delle Costruzioni" in the undergraduate program includes the necessary prerequisites.

Course unit content

The main topics that will be covered are as follows:

Scaling laws in structural mechanics.
Carbon-based structures (carbon fibers, carbon nanotubes, carbon nanotube fibers).
Structures made of brittle materials (glass, glass-ceramics, ceramic materials).
Rubbers and viscoelastic materials.

Full programme

Scaling Laws in Mechanics
Effective strength (limiting length of rupture). Discussion of Stussi. Structural coefficient for suspension cables, bent beams, and truss structures. Effective stiffness of inclined cables. Ernst's modulus. Example of cable-stayed bridges. Effective stiffness. Comparison of various materials in terms of effective strength and effective stiffness. Limit spans for suspension and cable-stayed bridges. Submerged tunnels. Cost comparison among various materials based on mechanical properties. Specific applications: space elevator.

Carbon-Based Structures
Ionic, metallic, and covalent bonds. Laws of attraction between atoms. Definition of stress state, strain, and elastic behavior in atomic ensembles.
Carbon. Carbon fibers: generalities, production, physical and mechanical properties. Carbon nanotubes. Carbon nanotube fibers. Mechanical, electrical, and thermal properties. Comparison with other materials. Tensile and bending behavior of bundles and fibers of carbon nanotubes: analytical model (kinematics, stress state on individual nanotubes, determination of the macroscopic stiffness of the fiber, influence of axial deformability of the nanotubes).
Structures based on carbon nanotube fibers. Modeling. Evaluation of the macroscopic properties of the fibers. Cable structures made from nanotube fibers. Modeling and optimization of the winding.

Structures Made of Brittle Materials
Plastic, brittle, and quasi-brittle materials. Modeling: plasticity theory, damage theory, fracture mechanics. Fracture mechanics. Inglis' solution. Griffith's energy balance. Stress Intensity Factor in modes I, II, and III. Cohesive fracture. Comparison of Griffith, Dugdale, and Barenblatt theories. Applications to glass, glass-ceramics, and ceramic materials.
Model with an equivalent crack. Static fatigue. Evans' model. Experimental determination of parameters governing static fatigue. Experimental methods for determining the strength of brittle materials.
Weakest ring in the chain model. Weibull statistics. Analysis in the Weibull plane. Generalized Weibull statistics: truncated Weibull, three-parameter, bilinear. Verification of structures made of brittle materials subjected to a generic stress state. Calculation of effective area.
Multiscale approach, micro-macro. From Pareto statistics of defects to determining Weibull statistics for macroscopic strength. Effect of production controls. Change in defectiveness due to corrosion and abrasion. Precompression states caused by thermal and chemical tempering processes in glasses.

Rubbers and Viscoelastic Materials
Entropic effects in rubbers. Calculation of stiffness based on statistical mechanics.
Polymers: glassy and rubbery states. Glass transition temperature. Linear viscoelasticity in the application field. Creep, relaxation, and dynamic tests. Material behavior analysis.
Laplace transform. Definition, theory, and examples. Application to solving differential equations of viscoelasticity. Mathematical models for viscoelastic materials. Maxwell model; standard linear viscoelastic solid model.
Wiechert model. Boltzmann's superposition principle. Relationship between relaxation and creep functions. Temperature effects. Simple materials. Time-temperature superposition. Viscoelastic analysis.

Bibliography

For all topics covered, lecture notes prepared by the instructor will be provided. Additional reference texts, from which specific chapters will be selected, include the following:

David Roylance, Mechanics of Materials, Wiley, 1995.
Ingo Müller, A History of Thermodynamics: The Doctrine of Energy and Entropy, Springer-Verlag, Berlin, 2007.
Soo-Jin Park, Carbon Fibers, Springer Nature, Singapore, 2018.
Gianni Royer-Carfagni, Gabriele Pisano, Probabilistic Mechanics of Brittle Materials, Book preprint

Teaching methods

The course employs an integrated teaching approach, combining theoretical lectures, practical activities, and project work to provide students with a solid understanding and applied skills in innovative materials and their structural applications.

Lectures: Fundamental theoretical concepts regarding the properties and applications of innovative materials are presented in class, including real-world case studies, practical examples, and discussions on current regulations. This component aims to solidify theoretical foundations and encourage critical thinking on advancements in advanced materials.

Project Work: Students complete projects that involve designing and optimizing a structure using innovative materials. Often conducted in groups, this work fosters collaboration and the pursuit of sustainable technical solutions. Projects are supervised by the instructor and may also include presentations and final reports.

Seminars and Workshops with Industry Experts: To provide a broader and up-to-date perspective, the course includes sessions with industry professionals and researchers, who share practical insights and highlight the latest innovations in advanced materials.

Independent Study and Research: Students are encouraged to explore specific topics in depth by consulting scientific articles and specialized literature. Support is provided for using bibliographic and digital resources, helping students develop independent research skills.

Tutoring and Online Support: The course offers tutoring and support sessions via online platforms to address questions and discuss class content. Students can interact with the instructor to receive personalized feedback and guidance on their projects.

These teaching methods are designed to develop both theoretical and practical competencies, preparing students for the professional application of innovative materials in engineering and multidisciplinary contexts.

Assessment methods and criteria

The assessment will take place through an oral exam, during which students will present an in-depth analysis of a specific topic covered in class. This in-depth study may consist of the analysis of one or more scientific articles suggested by the instructor or the presentation of a small project completed during the course. Internships at foreign universities are highly encouraged and can be funded through the Erasmus and Overworld programs. Currently, there are active collaborations with the Department of Chemical and Biomolecular Engineering, Materials Science and Nanoengineering at Rice University in Houston, TX, USA.

Other information

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2030 agenda goals for sustainable development

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