|
Failure Theory (material)
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 failu ... [...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 The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ... from 1970 to 1975. He was a professor of engineering at Brown University starting in 1975, and served as the de ... [...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 Bresler's 33 Flavors was an American ice cream chain founded in 1927. Its founder was Polish immigrant William J. Bresler, who died in 1985. In 1954, Bresler's began a fast food hamburger chain called Henry's Hamburgers. The Bresler's chain w ..., American ice cream chain * Bressler, a surname {{surname, Bresler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drucker Prager
Drucker (; {{IPA-de, ˈdʁʊkɐ, lang) is a surname of German and Jewish origin, and may refer to: Surname * 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 * Gerald Drucker (1925–2010), British bassist and photographer * 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 (1903–1988), Austrian footballer and coach * Linda Ryke-Drucker, American poker player *Hendrik Lodewijk Drucker (1857–1917), Dutch politician *Jason Drucker (born 2005), American child actor *Jean Dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Mises Yield Criterion
The maximum distortion 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 nonlinear elastic, viscoelastic, or linear elastic behavior. In materials science and engineering 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 yielding when the von Mises stress reaches a value known as yield strength, \sigma_\text. The von Mises stress is used to predict yielding of materials under complex loading from the results of uniaxial tensile tests. The von Mises stress satisfies the property where two stress states with equa ... [...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 \boldsymbol\sigma, 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 \sigma_ 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: :\mathbf^ = \mathbf e \cdot\boldsymbol\quad \text \quad T_^= \sigma_e_i, or, :\leftright\leftrightcdot \leftright The SI units of both stress tensor and traction vector are N/m2, 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 materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Stress
In continuum mechanics, the Cauchy stress tensor \boldsymbol\sigma, 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 \sigma_ that completely define the state of stress (mechanics), stress at a point inside a material in the Deformation (engineering), 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: :\mathbf^ = \mathbf e \cdot\boldsymbol\quad \text \quad T_^= \sigma_e_i, or, :\left[\right]=\left[\right]\cdot \left[\right]. The SI units of both stress tensor and traction vector are N/m2, corresponding to the stress scalar. The unit vector is Dimensionless quantity, dimensionless. The Cauchy stress tensor obeys the Covariant transformation, tensor transformation law under a change in the system of coordinates. A graphical representation of this transform ... [...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 The displacement of a body has two components: a rigid-body displacement and a deformation. * A rigid-body displacement consists of a simultaneous translation (physics) and rotation of the body without changing its shape or size. * Deformation implies the change in shape and/or size of the body from an initial or undeformed configuration \kappa_0(\mathcal B) to a current or deformed configuration \kappa_t(\mathcal B) (Figure 1). A change in the conf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (mechanics)
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 or 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 strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohesive Zone Model
The cohesive zone model (CZM) is a model in fracture mechanics Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics t ... 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 LEFM (Linear Elastic Fracture Mechanics), CTOD (Crack Tip open Displacement) are: *It is able to adequately predict the behaviour of uncracked structures, including those wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
