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Henri Tresca
Henri Édouard Tresca (12 October 1814 – 21 June 1885) was a French mechanical engineer, and a professor at the Conservatoire National des Arts et Métiers in Paris. Work on plasticity He is the father of the field of plasticity, or non-recoverable deformations, which he explored in an extensive series of experiments begun in 1864. He stated one of the first criterion of material failure, that now brings his name. The criterion specifies that a material would flow plastically if \ \sigma_=\sigma_1-\sigma_3 > \sigma_ Tresca's criterion is one of two main failure criteria used today for ductile materials. The second important criterion is due to Richard von Mises. See comparison on the image left: Design of the International Prototype Metre Tresca was also among the designers of the prototype metre bar that served as the first standard of length for the metric system. After the Convention of the Metre had been signed in 1875, the International Bureau of Weights and Mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dunkirk
Dunkirk (french: Dunkerque ; vls, label=French Flemish, Duunkerke; nl, Duinkerke(n) ; , ;) is a commune in the department of Nord in northern France.Commune de Dunkerque (59183) INSEE It lies from the border. It has the third-largest French harbour. The population of the commune in 2019 was 86,279. Etymology and language use The name of Dunkirk derives from '' or ' |
Viscoplasticity
Viscoplasticity is a theory in continuum mechanics that describes the rate-dependent inelastic behavior of solids. Rate-dependence in this context means that the deformation of the material depends on the rate at which loads are applied. The inelastic behavior that is the subject of viscoplasticity is plastic deformation which means that the material undergoes unrecoverable deformations when a load level is reached. Rate-dependent plasticity is important for transient plasticity calculations. The main difference between rate-independent plastic and viscoplastic material models is that the latter exhibit not only permanent deformations after the application of loads but continue to undergo a creep flow as a function of time under the influence of the applied load. The elastic response of viscoplastic materials can be represented in one-dimension by Hookean spring elements. Rate-dependence can be represented by nonlinear dashpot elements in a manner similar to viscoelasticity. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-D Elasticity
Linear elasticity is a mathematical model of how solid objects deform and become internally stressed due to prescribed loading conditions. It is a simplification of the more general nonlinear theory of elasticity and a branch of continuum mechanics. The fundamental "linearizing" assumptions of linear elasticity are: infinitesimal strains or "small" deformations (or strains) and linear relationships between the components of stress and strain. In addition linear elasticity is valid only for stress states that do not produce yielding. These assumptions are reasonable for many engineering materials and engineering design scenarios. Linear elasticity is therefore used extensively in structural analysis and engineering design, often with the aid of finite element analysis. Mathematical formulation Equations governing a linear elastic boundary value problem are based on three tensor partial differential equations for the balance of linear momentum and six infinitesimal str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain (materials Science)
In physics, deformation is the continuum mechanics transformation of a body from a ''reference'' configuration to a ''current'' configuration. A configuration is a set containing the positions of all particles of the body. A deformation can occur because of external loads, intrinsic activity (e.g. muscle contraction), body forces (such as gravity or electromagnetic forces), or changes in temperature, moisture content, or chemical reactions, etc. Strain is related to deformation in terms of ''relative'' displacement of particles in the body that excludes rigid-body motions. Different equivalent choices may be made for the expression of a strain field depending on whether it is defined with respect to the initial or the final configuration of the body and on whether the metric tensor or its dual is considered. In a continuous body, a deformation field results from a stress field due to applied forces or because of some changes in the temperature field of the body. The relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (physics)
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elongation which is also known as deformation, like the stretching of an elastic band, it is called tensile stress. But, when the forces result in the compression of an object, it is called compressive stress. It results when forces like Tension (physics), tension or Compression (physics), compression act on a body. The greater this force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Therefore, stress is measured in newton per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while deformation (mechanics)#Strain, strain is the measure of the deformation of the material. For example, when a solid vertic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yield (engineering)
In materials science and engineering, the yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation. The yield strength or yield stress is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, making the precise yield point difficult to determine. In such a case, the offset yiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adiabatic Shear Band
In physics, mechanics and engineering, an adiabatic shear band is one of the many mechanisms of failure that occur in metals and other materials that are deformed at a high rate in processes such as metal forming, machining and ballistic impact. Adiabatic shear bands are usually very narrow bands, typically 5-500 μm wide and consisting of highly sheared material. ''Adiabatic'' is a thermodynamic term meaning an absence of heat transfer – the heat produced is retained in the zone where it is created. (The opposite extreme, where all heat that is produced is conducted away, is ''isothermal''.) Deformation It is necessary to include some basics of plastic deformation to understand the link between heat produced and the plastic work done. If we carry out a compression test on a cylindrical specimen to, say, 50% of its original height, the stress of the work material will increase usually significantly with reduction. This is called ‘work hardening’. During work hardening, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Mises Stress
The term ''von'' () is used in German language surnames either as a nobiliary particle indicating a noble patrilineality, or as a simple preposition used by commoners that means ''of'' or ''from''. Nobility directories like the ''Almanach de Gotha'' often abbreviate the noble term ''von'' to ''v.'' In medieval or early modern names, the ''von'' particle was at times added to commoners' names; thus, ''Hans von Duisburg'' meant "Hans from he city ofDuisburg". This meaning is preserved in Swiss toponymic surnames and in the Dutch or Afrikaans ''van'', which is a cognate of ''von'' but does not indicate nobility. Usage Germany and Austria The abolition of the monarchies in Germany and Austria in 1919 meant that neither state has a privileged nobility, and both have exclusively republican governments. In Germany, this means that legally ''von'' simply became an ordinary part of the surnames of the people who used it. There are no longer any legal privileges or constraints assoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yield Surface
A yield surface is a five-dimensional surface in the six-dimensional space of stresses. The yield surface is usually convex and the state of stress of ''inside'' the yield surface is elastic. When the stress state lies on the surface the material is said to have reached its yield point and the material is said to have become plastic. Further deformation of the material causes the stress state to remain on the yield surface, even though the shape and size of the surface may change as the plastic deformation evolves. This is because stress states that lie outside the yield surface are non-permissible in rate-independent plasticity, though not in some models of viscoplasticity.Simo, J. C. and Hughes, T,. J. R., (1998), Computational Inelasticity, Springer. The yield surface is usually expressed in terms of (and visualized in) a three-dimensional principal stress space ( \sigma_1, \sigma_2 , \sigma_3), a two- or three-dimensional space spanned by stress invariants ( I_1, J_2, J_3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The 72 Names On The Eiffel Tower
On the Eiffel Tower, 72 names of French scientists, engineers, and mathematicians are engraved in recognition of their contributions. Gustave Eiffel chose this "invocation of science" because of his concern over the protests against the tower. The engravings are found on the sides of the tower under the first balcony, in letters about tall, and originally painted in gold. The engraving was painted over at the beginning of the 20th century and restored in 1986–87 by Société Nouvelle d'exploitation de la Tour Eiffel, the company that the city of Paris contracts to operate the Tower. The repainting of 2010–11 restored the letters to their original gold colour. There are also names of the engineers who helped build the Tower and design its architecture on a plaque on the top of the Tower, where a laboratory was built as well. List Location The list is split in four parts (for each side of the tower). The sides have been named after the parts of Paris that each side faces: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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