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Material Failure
Material failure theory is an interdisciplinary field of materials science and solid mechanics which attempts to predict the conditions under which solid materials fail under the action of external loads. The failure of a material is usually classified into brittle failure (fracture) or ductile failure ( yield). Depending on the conditions (such as temperature, state of stress, loading rate) most materials can fail in a brittle or ductile manner or both. However, for most practical situations, a material may be classified as either brittle or ductile. In mathematical terms, failure theory is expressed in the form of various failure criteria which are valid for specific materials. Failure criteria are functions in stress or strain space which separate "failed" states from "unfailed" states. A precise physical definition of a "failed" state is not easily quantified and several working definitions are in use in the engineering community. Quite often, phenomenological failure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materials Science
Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries. The intellectual origins of materials science stem from the Age of Enlightenment, when researchers began to use analytical thinking from chemistry, physics, and engineering to understand ancient, phenomenological observations in metallurgy and mineralogy. Materials science still incorporates elements of physics, chemistry, and engineering. As such, the field was long considered by academic institutions as a sub-field of these related fields. Beginning in the 1940s, materials science began to be more widely recognized as a specific and distinct field of science and engineering, and major technical universities around the world created dedicated schools for its study. Materials scientists emphasize understanding how the history of a material (''processing'') influences its struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Needleman
Alan Needleman (born September 2, 1944) is a professor of materials science & engineering at Texas A&M University. Prior to 2009, he was Florence Pirce Grant University Professor of Mechanics of Solids and Structures at Brown University in Providence, Rhode Island. Early life and education Needleman received his B.S. from the University of Pennsylvania in 1966, an M.S. and Ph.D. from Harvard University in 1967 and 1970 respectively, advised by John W. Hutchinson. Research and career He was an instructor and assistant professor in the Department of Applied Mathematics at the Massachusetts Institute of Technology from 1970 to 1975. He was a professor of engineering at Brown University starting in 1975, and served as the dean of the Engineering Department from 1988 to 1991. He was the chair of the Applied Mechanics Division. Needleman's main research interests are in the computational modeling of deformation and fracture processes in structural materials, in particular m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bresler Pister Yield Criterion
Bresler is a surname. Notable people with the surname include: * Anton Bresler (born 1988), South African rugby union player * Jerry Bresler (1914–2000), American songwriter, conductor * Jerry Bresler (1908–1977), American film producer See also * Bresler Pister yield criterion * Bresler's Ice Cream, American ice cream chain * Bressler, a surname {{surname, Bresler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drucker Prager
Drucker (; ) is an occupational surname of German and Dutch origin. Notable people and characters with the surname include: People *Adam Drucker (born 1977), American rapper and poet, known by the stage name Doseone * Adolphus Drucker (1868–1903), Dutch-born English politician * Amy Drucker (1873–1951), British artist * Daniel C. Drucker (1918–2001), American engineer and academic * Daniel J. Drucker (born 1956), Canadian endocrinologist * Ernest Drucker (1940–2025), American public health researcher *Gerald Drucker (1925–2010), British bassist and photographer *Henry Drucker (1942–2002), American political scientist and university fundraiser, based in Britain * Iosif Druker (1822–1879), Russian Jewish violin virtuoso, known by the popular name Stempenyu * Itzhak Drucker (born 1947), Israeli footballer *Léa Drucker (born 1972), French actress * Leon Drucker (born 1961), American bassist, known by the stage name of Lee Rocker, son of Stanley * Leopold Drucker (1903–1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Mises Yield Criterion
In continuum mechanics, the maximum distortion energy criterion (also von Mises yield criterion) states that yielding of a ductile material begins when the second invariant of deviatoric stress J_2 reaches a critical value. It is a part of plasticity theory that mostly applies to ductile materials, such as some metals. Prior to yield, material response can be assumed to be of a linear elastic, nonlinear elastic, or viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ... behavior. In materials science and engineering, the von Mises yield criterion is also formulated in terms of the von Mises stress or equivalent tensile stress, \sigma_\text. This is a scalar value of stress that can be computed from the Cauchy stress tensor. In this case, a material is said to start y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tresca Yield Criterion
A yield surface is a five-dimensional surface in the six-dimensional space of Stress (mechanics), stresses. The yield surface is usually convex polytope, 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 (engineering), yield point and the material is said to have become Plasticity (physics), 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 plasticity (physics), 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 Stress (physics)#Principal stresses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cauchy Stress Tensor
In continuum mechanics, the Cauchy stress tensor (symbol \boldsymbol\sigma, named after Augustin-Louis Cauchy), also called true stress tensor or simply stress tensor, completely defines the state of stress at a point inside a material in the deformed state, placement, or configuration. The second order tensor consists of nine components \sigma_ and relates a unit-length direction vector e to the ''traction vector'' T(e) across an imaginary surface perpendicular to e: :\mathbf^ = \mathbf e \cdot\boldsymbol\quad \text \quad T_^= \sum_\sigma_e_i. The SI base units of both stress tensor and traction vector are newton per square metre (N/m2) or pascal (Pa), corresponding to the stress scalar. The unit vector is dimensionless. The Cauchy stress tensor obeys the tensor transformation law under a change in the system of coordinates. A graphical representation of this transformation law is the Mohr's circle for stress. The Cauchy stress tensor is used for stress analysis of mater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite Strain Theory
In continuum mechanics, the finite strain theory—also called large strain theory, or large deformation theory—deals with deformations in which strains and/or rotations are large enough to invalidate assumptions inherent in infinitesimal strain theory. In this case, the undeformed and deformed configurations of the continuum are significantly different, requiring a clear distinction between them. This is commonly the case with elastomers, plastically deforming materials and other fluids and biological soft tissue. Displacement field Deformation gradient tensor The deformation gradient tensor \mathbf F(\mathbf X,t) = F_ \mathbf e_j \otimes \mathbf I_K is related to both the reference and current configuration, as seen by the unit vectors \mathbf e_j and \mathbf I_K\,\!, therefore it is a '' two-point tensor''. Two types of deformation gradient tensor may be defined. Due to the assumption of continuity of \chi(\mathbf X,t)\,\!, \mathbf F has the inverse \mathbf H = \ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (mechanics)
In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, 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 dimension of force per area, with SI units of newtons 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 ''strain'' is the measure of the relative deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohesive Zone Model
The cohesive zone model (CZM) is a model in fracture mechanics where fracture formation is regarded as a gradual phenomenon and separation of the crack surfaces takes place across an extended crack tip, or cohesive zone, and is resisted by cohesive tractions. The origin of this model can be traced back to the early sixties by Dugdale (1960) and Barenblatt (1962) to represent nonlinear processes located at the front of a pre-existent crack. Description The major advantages of the CZM over the conventional methods in fracture mechanics like those including Fracture_mechanics#Linear_elastic_fracture_mechanics, LEFM (Linear Elastic Fracture Mechanics), Crack_tip_opening_displacement, CTOD (Crack Tip open Displacement) are: *It is able to adequately predict the behaviour of uncracked structures, including those with blunt notches. *Size of non-linear zone need not be negligible in comparison with other dimensions of the cracked geometry in CZM, while in other conventional methods, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
