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Ogden–Roxburgh Model
The Ogden–Roxburgh model is an approach which extends hyperelastic material models to allow for the Mullins effect. It is used in several commercial finite element The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat t ... codes, and is named for R.W. Ogden and D. G. Roxburgh. The basis of pseudo-elastic material models is a hyperelastic second Piola–Kirchhoff stress \boldsymbol_0, which is derived from a suitable strain energy density function W(\boldsymbol): : \boldsymbol = 2 \frac \quad . The key idea of pseudo-elastic material models is that the stress during the first loading process is equal to the basic stress \boldsymbol_0. Upon unloading and reloading \boldsymbol_0 is multiplied by a positive softening function \eta. The function \eta thereby depends on the strain energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperelastic Material
A hyperelastic or Green elastic materialR.W. Ogden, 1984, ''Non-Linear Elastic Deformations'', , Dover. is a type of constitutive model for ideally elastic material for which the stress–strain relationship derives from a strain energy density function. The hyperelastic material is a special case of a Cauchy elastic material. For many materials, linear elastic models do not accurately describe the observed material behaviour. The most common example of this kind of material is rubber, whose stress- strain relationship can be defined as non-linearly elastic, isotropic and incompressible. Hyperelasticity provides a means of modeling the stress–strain behavior of such materials. The behavior of unfilled, vulcanized elastomers often conforms closely to the hyperelastic ideal. Filled elastomers and biological tissues are also often modeled via the hyperelastic idealization. Ronald Rivlin and Melvin Mooney developed the first hyperelastic models, the Neo-Hookean and Mooney–R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullins Effect
The Mullins effect is a particular aspect of the mechanical response in filled rubbers, in which the stress–strain curve depends on the maximum loading previously encountered. The phenomenon, named for rubber scientist Leonard Mullins, working at the Tun Abdul Razak Research Centre in Hertford, can be idealized for many purposes as an instantaneous and irreversible softening of the stress–strain curve that occurs whenever the load increases beyond its prior all-time maximum value. At times, when the load is less than a prior maximum, nonlinear elastic behavior prevails. The effect should not be confused with the Payne effect. Although the term "Mullins effect" is commonly applied to stress softening in filled rubbers, the phenomenon is common to all rubbers, including "gums" (rubber lacking filler). As first shown by Mullins and coworkers, the retraction stresses of an elastomer are independent of carbon black Carbon black (subtypes are acetylene black, channel black, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite Element
The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat transfer, fluid flow, mass transport, and electromagnetic potential. The FEM is a general numerical method for solving partial differential equations in two or three space variables (i.e., some boundary value problems). To solve a problem, the FEM subdivides a large system into smaller, simpler parts that are called finite elements. This is achieved by a particular space discretization in the space dimensions, which is implemented by the construction of a mesh of the object: the numerical domain for the solution, which has a finite number of points. The finite element method formulation of a boundary value problem finally results in a system of algebraic equations. The method approximates the unknown function over the domain. The simple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raymond Ogden
Raymond William Ogden (born 19 September 1943) is a British applied mathematician. He is the George Sinclair Professor of Mathematics at the Department of Mathematics and Statistics of the University of Glasgow. Education Ogden earned his BA and PhD degrees from the University of Cambridge in 1970, under the supervision of Rodney Hill. His thesis was entitled ''On Constitutive Relations for Elastic and Plastic Materials''. Work Ogden's research has been focused on the nonlinear theory of elasticity and its applications. His theoretical contributions include the derivation of exact solutions of nonlinear boundary value problems, for both compressible and incompressible materials, and an analysis of the linear and nonlinear stability of pre-stressed bodies and related studies of elastic wave propagation. In the field of applications, Ogden worked on modelling the elastic and inelastic behaviour of rubber-like solids. He has also made contributions to the biomechanics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piola–Kirchhoff Stress Tensor
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] |
Strain Energy Density Function
A strain energy density function or stored energy density function is a scalar-valued function that relates the strain energy density of a material to the deformation gradient. : W = \hat(\boldsymbol) = \hat(\boldsymbol^T\cdot\boldsymbol) =\bar(\boldsymbol) = \bar(\boldsymbol^\cdot\boldsymbol)=\tilde(\boldsymbol,\boldsymbol) Equivalently, : W = \hat(\boldsymbol) = \hat(\boldsymbol^T\cdot\boldsymbol\cdot\boldsymbol) =\tilde(\boldsymbol,\boldsymbol) where \boldsymbol is the (two-point) deformation gradient tensor, \boldsymbol is the right Cauchy–Green deformation tensor, \boldsymbol is the left Cauchy–Green deformation tensor, and \boldsymbol is the rotation tensor from the polar decomposition of \boldsymbol. For an anisotropic material, the strain energy density function \hat(\boldsymbol) depends implicitly on reference vectors or tensors (such as the initial orientation of fibers in a composite) that characterize internal material texture. The spatial representa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubber Chemistry And Technology
''Rubber Chemistry and Technology'' is a quarterly peer-reviewed scientific journal covering fundamental research and technical developments relating to chemistry, materials science, and engineering of rubber, elastomers, and related materials. It was established in 1928, with Carroll C. Davis as its first editor-in-chief. The current editor-in-chief is Christopher G. Robertson. The journal is published by the American Chemical Society's Rubber Division. The journal currently publishes four issues per year containing original research contributions and review articles. Abstracting and indexing The journal is abstracted indexed in: According to the ''Journal Citation Reports'', the journal has a 2021 impact factor of 2.081. Past editors The following persons have been editors-in-chief of the journal: *Christopher G. Robertson (Polymer Technology Services; July 2020-present) *William V. Mars, (Endurica; 2010-June 2020) *Krishna Baranwal ( Akron Rubber Development Lab; 2002-2009) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuum Mechanics
Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such models in the 19th century. Explanation A continuum model assumes that the substance of the object fills the space it occupies. Modeling objects in this way ignores the fact that matter is made of atoms, and so is not continuous; however, on length scales much greater than that of inter-atomic distances, such models are highly accurate. These models can be used to derive differential equations that describe the behavior of such objects using physical laws, such as mass conservation, momentum conservation, and energy conservation, and some information about the material is provided by constitutive relationships. Continuum mechanics deals with the physical properties of solids and fluids which are independent of any particular coordinate sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasticity (physics)
In physics and materials science, elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to ''plasticity'', in which the object fails to do so and instead remains in its deformed state. The physical reasons for elastic behavior can be quite different for different materials. In metals, the atomic lattice changes size and shape when forces are applied (energy is added to the system). When forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied. Hooke's law states that the force required to deform elastic objects should be directly proportional to the distanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubber Properties
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and Indonesia are three of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers. Currently, rubber is harvested mainly in the form of the latex from the rubber tree (''Hevea brasiliensis'') or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into the rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale. Natural rubber is used extensively in many applications and products, either alone or in combination with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
