Introduction to Structural Mechanics provides students with the basic knowledge of mechanics of materials and structures. This knowledge allows students to solve simple problems in the statics of elastic beams, and to acquire the core knowledge required for courses in structural design. The course is taught in the second year of the Degree in Civil Engineering. This degree aims at providing tools for the design, construction, maintenance and management of civil structures and infrastructures, such as buildings, bridges, tunnels, transport systems, hydraulic works and land protection. As part of this process, the course aims to provide adequate knowledge: 1) of the laws governing the equilibrium of rigid and deformable systems; 2) of beam theory; 3) methods for calculating stresses in beam framework; 4) assess the resistance of a structure. At the end of the course students will be able to: 1) be acquainted with technical language; 2) analytically represent and solve simple problems of statics of structures in civil engineering; 3) to understand the limits of the models used; 4) to assess the safety of a structural element.
scheda docente
materiale didattico
Beam kinematics: displacement field and strain measurements.
Constitutive equations for the elastic beam. Axial behavior, flexural behavior, shear behavior. Uniform thermal variation, butterfly thermal variation, affine thermal variation.
Equation of the tensioned beam. Equation of the inflected beam (elastic line) in the Euler-Bernoulli model. Extension to Timoshenko's model. Fitting conditions and problem formulation for beam systems. Kinematic and static performance of internal constraints.
Identity of virtual works. Notion of congruent system. Notion of balanced system. External virtual work. Internal virtual work. Virtual Work Theorem, statement and proof. Application of the Virtual Work Principle to the calculation of displacements and rotations in statically determinate structures.
Method of forces. Notion of a principal system. Application of the method to repeatedly hyperstatic systems. Müller-Breslau equations. Flexibility matrix. Effect of yielding and thermal distortions.
Continuous beams. Equation of three moments.
Saint Venant's problem. Saint Venant's postulate. Simple and compound stresses. Semi-inverse method.
Centered normal force. Straight deflection. Deflection deflected. Tensoflexion, Pressoflexion. Central core of inertia. Torsion in circular sections. The compact circular section. The hollow circular section.
Torsion in compact sections of any shape. Neumann's problem. Elliptical section. Polygonal sections. The hydrodynamic analogy for tangential stresses. Thin rectangular section. Open sections composed of thin rectangles. Thin-walled hollow sections: Bredt's theory. Composite thin sections. Pluriconconnected sections.
Flexure and shear. Distribution of normal stresses. Distribution of tangential stresses: approximate treatment of Jourawsky. Applicability of Jourawsky's formula.
Open thin sections. Rectangular thin section. Double-T thin section. U and H thin sections. Closed thin sections. Symmetrical box section. Straight cut. Deviated cut. Symmetrical compact sections. Compound stresses of straight cut and twist. The center of shear. Tangential shear and torsion stresses. Determination of the center of shear.
Strength criteria. Strength criteria for brittle materials. Strength criteria for ductile materials.
The beam: structural analysis and verification. Extension of Saint Venant's theory. Strength criteria for Saint Venant's solid.
Steen Krenk & Jan Høgsberg, "Statics and Mechanics of Structures", Springer 2013.
M. Capurso, Lezioni di Scienza delle Costruzioni, Pitagora Editrice, 1984.
E. Sacco, Lezioni di Scienza delle Costruzioni, 2016.
Solved problems.
Programma
The elastic equilibrium problem for the beam and its formulation.Beam kinematics: displacement field and strain measurements.
Constitutive equations for the elastic beam. Axial behavior, flexural behavior, shear behavior. Uniform thermal variation, butterfly thermal variation, affine thermal variation.
Equation of the tensioned beam. Equation of the inflected beam (elastic line) in the Euler-Bernoulli model. Extension to Timoshenko's model. Fitting conditions and problem formulation for beam systems. Kinematic and static performance of internal constraints.
Identity of virtual works. Notion of congruent system. Notion of balanced system. External virtual work. Internal virtual work. Virtual Work Theorem, statement and proof. Application of the Virtual Work Principle to the calculation of displacements and rotations in statically determinate structures.
Method of forces. Notion of a principal system. Application of the method to repeatedly hyperstatic systems. Müller-Breslau equations. Flexibility matrix. Effect of yielding and thermal distortions.
Continuous beams. Equation of three moments.
Saint Venant's problem. Saint Venant's postulate. Simple and compound stresses. Semi-inverse method.
Centered normal force. Straight deflection. Deflection deflected. Tensoflexion, Pressoflexion. Central core of inertia. Torsion in circular sections. The compact circular section. The hollow circular section.
Torsion in compact sections of any shape. Neumann's problem. Elliptical section. Polygonal sections. The hydrodynamic analogy for tangential stresses. Thin rectangular section. Open sections composed of thin rectangles. Thin-walled hollow sections: Bredt's theory. Composite thin sections. Pluriconconnected sections.
Flexure and shear. Distribution of normal stresses. Distribution of tangential stresses: approximate treatment of Jourawsky. Applicability of Jourawsky's formula.
Open thin sections. Rectangular thin section. Double-T thin section. U and H thin sections. Closed thin sections. Symmetrical box section. Straight cut. Deviated cut. Symmetrical compact sections. Compound stresses of straight cut and twist. The center of shear. Tangential shear and torsion stresses. Determination of the center of shear.
Strength criteria. Strength criteria for brittle materials. Strength criteria for ductile materials.
The beam: structural analysis and verification. Extension of Saint Venant's theory. Strength criteria for Saint Venant's solid.
Testi Adottati
P. Casini, M. Vasta, "Scienza delle costruzioni", Città Studi Edizioni 2016.Steen Krenk & Jan Høgsberg, "Statics and Mechanics of Structures", Springer 2013.
M. Capurso, Lezioni di Scienza delle Costruzioni, Pitagora Editrice, 1984.
E. Sacco, Lezioni di Scienza delle Costruzioni, 2016.
Solved problems.
Modalità Frequenza
Attendance is recommended but not mandatory.Modalità Valutazione
The exam is divided into a written and oral test. A successful written test allows the access to the oral examination. The latter starts with a discussion of the written test, followed by questions on the topics of the course.