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Lecture

Centroids and Stress-Strain Diagrams

In course

CIVIL-238: Structural mechanics (for GC)

The course discusses the basic principles of structural mechanics, analyzing the performance of materials and structures against loading and focuses on the stress strain relationships and the effect of axial, bending, shear and torsional loadings on engin ...

Description

This lecture covers the concept of centroids of plane areas, explaining how to calculate the centroid coordinates and locate it for different types of areas. It also discusses normal stresses in beams, illustrating the evaluation of normal strains in various profiles and reinforced concrete beams.

Instructors (2)

Anastasios Vassilopoulos

PERSONAL INFORMATION Name : Anastasios P. Vassilopoulos email : anastasios.vassilopoulos@epfl.ch Tel: 41 21 6936393 Fax: 41 21 6936240 SUMMARY OF QUALIFICATIONS 1995: Dipl. Mechanical Engineer, University of Patras, Greece 2001: Dr Mechanical Engineer, Doctoral thesis in fatigue of composite materials from the Dept. Mechanical Engineering and Aeronautics, University of Patras, Greece CURRENT POSITION Senior Scientist (MER), Composite Construction Laboaratory (CCLab), EPFL PREVIOUS POSITIONS 2006-2012 Research and Teaching Associate, Composite Construction Laboaratory (CCLab), EPFL 2002-2006 Assisstant Professor, Technological Educational Institute (TEI) of Patras, Greece 2001-2003 Post-doctoral Research associate, (Part-time) Dept. Mechanical Engineering and Aeronautics of the University of Patras, Greece. EDUCATION 1990 - 1995 Graduate student, Dept. Mechanical Engineering and Aeronautics, University of Patras, Greece October 1994-January 1995 Dept. Mechanical Engineering, University of Bristol, U.K. (In the frame of Erasmus project for the final year thesis, under the supervision of Prof. R. D. Adams) 1995 - 2000 Research assistant, Dept. Mechanical Engineering and Aeronautics, University of Patras. LANGUAGES English, Greek, French COMMUNITY ACTIVITIES (Member of) Council of the European Society of Composite Materials (ESCM) Council of the European Society of Experimental Mechanics (EuraSEM) The European Structural Integrity Society (ESIS) The European Energy Research Alliance (EERA, JP WIND) The Technical Chamber of Greece (TCG) The Hellenic Association of Mechanical & Electrical Engineers SCIENTIFIC-RESEARCH INTERESTS Experimental methods for the study of the behavior of composite materials under static and fatigue loading Development of analytical methods for the study of the behavior of FRP composite materials under variable amplitude complex stress states Development of fatigue life prediction methodologies for composite materials and structures Design of constructions with composite materials

Dimitrios Lignos

Prof. Lignos joined the École Polytechnique Féderale de Lausanne (EPFL) in 2016 from McGill University in Canada where he was a tenured Associate Professor and a William Dawson Scholar for Infrastructure Resilience. He holds a diploma (National Technical University of Athens, NTUA, 2003), M.S. (Stanford University, 2004) and Ph.D. (Stanford University, 2008). In addition, he was a post-doctoral scientist at Stanford University (2009) and in Kyoto University (2010). Prof. Lignos teaches graduate and undergraduate courses in seismic design, nonlinear behaviour of steel and composite structures as well as supplemental damping systems, Structural Stability, Nonlinear Analysis and Performance-based Earthquake Engineering. His awards for teaching, research and service in Civil Engineering include the 2011 Outstanding Teaching Award (Faculty of Engineering, McGill University), as well as the Outstanding reviewer (2012, 2013) award from ASCE, the 2013 State-of-the-Art in Civil Engineering Award by ASCE and the 2014 Christophe Pierre Award for Research Excellence - Early Career. Just recently, he received the 2019 Walter L. Huber Civil Engineering Research Prize from ASCE for significant contributions in developing state of the art methods to simulate extreme limit states in steel structures.Prof. Lignos is a member of ASCE and the Earthquake Engineering Research Institute. He acts as an Associate Editor for Metal Structures and Seismic Effects of the ASCE Journal of Structural Engineering. He joined the Editorial Board of Earthquake Spectra and Earthquake Engineering and Structural Dynamics International journals. He serves as an acting member of the CEN/TC 250/SC 8/WG 2 and has been selected as a member of the Project Team (PT2) for the Eurocode 8-Part 1 Current Revisions for Steel and Composite Structures. He is also a member of the Canadian Standards Association (CSA) S16 technical committee for Steel Structures. Prof. Lignos is involved as a NEHRP consultant in numerous research-to-practice projects related to the behaviour and nonlinear modelling and analysis of structures applicable to the engineering practice through the Applied Technology Council (ATC). Detailed Curriculum Vitae (last update September 2018)

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Related concepts (32)

Cauchy stress tensor

In continuum mechanics, the Cauchy stress tensor , true stress tensor, or simply called the stress tensor is a second order tensor named after Augustin-Louis Cauchy. The tensor consists of nine components that completely define the state of stress at a point inside a material in the deformed state, placement, or configuration. The tensor relates a unit-length direction vector e to the traction vector T(e) across an imaginary surface perpendicular to e: or, The SI units of both stress tensor and traction vector are N/m2, corresponding to the stress scalar.

Stress (mechanics)

In continuum mechanics, stress is a physical quantity that describes forces present during deformation. An object being pulled apart, such as a stretched elastic band, is subject to tensile stress and may undergo elongation. An object being pushed together, such as a crumpled sponge, is subject to compressive stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has units of force per area, such as newtons per square meter (N/m2) or pascal (Pa).

Area

Area is the measure of a region's size on a surface. The area of a plane region or plane area refers to the area of a shape or planar lamina, while surface area refers to the area of an open surface or the boundary of a three-dimensional object. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat.

Stress–strain curve

In engineering and materials science, a stress–strain curve for a material gives the relationship between stress and strain. It is obtained by gradually applying load to a test coupon and measuring the deformation, from which the stress and strain can be determined (see tensile testing). These curves reveal many of the properties of a material, such as the Young's modulus, the yield strength and the ultimate tensile strength. Generally speaking, curves representing the relationship between stress and strain in any form of deformation can be regarded as stress–strain curves.

Numerical integration

In analysis, numerical integration comprises a broad family of algorithms for calculating the numerical value of a definite integral, and by extension, the term is also sometimes used to describe the numerical solution of differential equations. This article focuses on calculation of definite integrals. The term numerical quadrature (often abbreviated to quadrature) is more or less a synonym for numerical integration, especially as applied to one-dimensional integrals.

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