Lecture

Torsion of Non-Circular Bars

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In course

MICRO-200: Mechanism Design I

Ce cours introduit les bases de la mécanique des structures : calcul des contraintes et déformations provoquées par les forces extérieures et calcul des déformations. Ces enseignements théoriques sont appliqués à la conception des éléments importants des m ...

Description

This lecture covers the introduction to torsion, relative stresses and strains, and the determination of internal torques for prismatic segments of non-circular bars. It also explains the angle of torsion for complete bars, the shear stress profile in concentric bars made of multiple materials, and the torsional stiffness of bars. Additionally, it discusses the torsion of composite bars composed of different materials, the relative shear strain, and the maximum shear stress in each material. The lecture concludes with examples demonstrating the application of the concepts discussed.

Instructors (4)

Simon Nessim Henein

Born in 1973 and of Egyptian-Swiss nationality, Simon Henein grew up in Cairo. He obtained an engineering degree at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in 1996 and went on to complete his doctorate at the EPFL in 2000. In 2001, he published the book “Conception des guidages flexibles” which has become a reference in precision engineering. He then joined the Centre Suisse d’Electronique et Microtechnique (CSEM), Neuchatel, Switzerland, where he conceived and developed mechanisms for robotic, aerospace, medical and watchmaking applications. He pursued his research career at the Paul Scherrer Institute, Villigen, Switzerland, where he developed instruments for the Swiss Light Source Synchrotron (SLS). Since November 1st, 2012, he is associate professor in microengineering at the EPFL, holder of the Patek Philippe Chair and director of the Micromechanical and horological design laboratory (Instant-Lab).

Herbert Shea

Expertise soft robotics, wearable haptics, electrostatic actuators, EHD Mission My lab develops flexible polymer-based actuators for a wide range of applications including haptics and soft robotics. More info at https://www.epfl.ch/labs/lmts/ Links from EPFL-LMTS Lab webpage People Research ActivitiesPublications TeachingPublications and Conference papers Link to my lab Education PhD | Physics 1997 – 1997 Harvard University MA | Physics 1993 – 1993 Harvard University

Olivier Chappuis

Danick Briand

Expertise MEMS and MicrosystemsFlexible and Printed ElectronicsEnergy Harvesting and PowerMEMSSmart Sensing SystemsAdvanced Gas Sensing TechnologiesMicrofabrication and Printing technologiesMicrosystems Integration and Packaging Expertise MEMS and MicrosystemsFlexible and Printed ElectronicsEnergy Harvesting and PowerMEMSSmart Sensing SystemsAdvanced Gas Sensing TechnologiesMicrofabrication and Printing technologiesMicrosystems Integration and Packaging Mission Environmentally-friendly technology is a rapid

Official source

Ontological neighbourhood

Chemical engineering

Materials science: Deformation of materials

Related concepts (32)

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).

Shear modulus

In materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is a measure of the elastic shear stiffness of a material and is defined as the ratio of shear stress to the shear strain: where = shear stress is the force which acts is the area on which the force acts = shear strain. In engineering , elsewhere is the transverse displacement is the initial length of the area. The derived SI unit of shear modulus is the pascal (Pa), although it is usually expressed in gigapascals (GPa) or in thousand pounds per square inch (ksi).

Shear strength

In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a material along a plane that is parallel to the direction of the force. When a paper is cut with scissors, the paper fails in shear. In structural and mechanical engineering, the shear strength of a component is important for designing the dimensions and materials to be used for the manufacture or construction of the component (e.

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.

Stiffness

Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. The stiffness, of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single degree of freedom (DOF) (for example, stretching or compression of a rod), the stiffness is defined as where, is the force on the body is the displacement produced by the force along the same degree of freedom (for instance, the change in length of a stretched spring) In the International System of Units, stiffness is typically measured in newtons per meter ().

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Torsion of Non-Circular Bars

Covers the introduction to torsion, shear stress, and angle of torsion in non-circular bars.

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Torsion: Deriving Hooke's Law and Solving Torsion Problems

Covers torsional loads, Hooke's law derivation, solving problems, and examples in hollow and composite shafts.

Introduction to Torsion: Relative Stresses and Strains

Introduces torsion, explaining relative stresses and strains in bars, shear modulus, and torque transmission.

Normal Stresses: Internal Stress and Strain