Jumat, 05 April 2013

Modulus Resilience



Resilience is the ability of a material to absorb energy when it is deformed elastically, and release that energy upon unloading. The modulus of resilience is defined as the maximum energy that can be absorbed per unit volume without creating a permanent distortion. It can be calculated by integrating the stress-strain curve from zero to the elastic limit. In uniaxial tension,
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where Ur is the modulus of resilience, σy is the yield strength, and E is the Young's modulus
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References
1. Campbell, Flake C. (2008). Elements of Metallurgy and Engineering Alloys. ASM International. p. 206. ISBN 9780871708670.





Young's modulus , also known as the tensile modulus , is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's lawholds. [ 1 ] In solid mechanics , the slope of the stress-strain curve at any point is called the tangent modulus . The tangent modulus of the initial, linear portion of a stress-strain curve is called Young's modulus . It can be experimentally determined from the slope of astress-strain curve created during tensile tests conducted on a sample of the material. In anisotropic materials, Young's modulus may have different values depending on the direction of the applied force with respect to the material's structure.
It is also commonly called the elastic modulus or modulus of elasticity , because Young's modulus is the most common elastic modulus used, but there are other elastic moduli measured, too, such as the bulk modulus and the shear modulus .
Young's modulus is named after Thomas Young , the 19th century British scientist. However, the concept was developed in 1727 byLeonhard Euler , and the first experiments that used the concept of Young's modulus in its current form were performed by the Italian scientist Giordano Riccati in 1782, predating Young's work by 25 years. [ 2 ]
Young's modulus, E , can be calculated by dividing the tensile stress by the tensile strain in the elastic (initial, linear) portion of thestress-strain curve :
Description:  E \equiv \frac{\mbox {tensile stress}}{\mbox {tensile strain}} = \frac{\sigma}{\varepsilon}= \frac{F/A_0}{\Delta L/L_0} = \frac{F L_0} {A_0 \Delta L}
Where :
E is the Young's modulus (modulus of elasticity)
F is the force exerted on an object under tension;
0 is the original cross-sectional area through which the force is applied;
ΔL is the amount by which the length of the object changes;
0 is the original length of the object.
Material
lbf/in² (psi)
Steel (ASTM-A36)
29,000,000

References
1.     ^ Nic, M.; Jirat, J.; Kosata, B., eds. (2006–). "modulus of elasticity (Young's modulus), E " . IUPAC Compendium of Chemical Terminology (Online ed.). doi :10.1351/goldbook.M03966 . ISBN 0-9678550-9-8 .
2.     ^ The Rational Mechanics of Flexible or Elastic Bodies, 1638–1788 : Introduction to Leonhardi Euleri Opera Omnia, vol. X and XI, Seriei Secundae. Orell Fussli.
3.     a b c d e f g h i j k l m n o p q r "Elastic Properties and Young Modulus for some Materials" . The Engineering ToolBox .Retrieved 2012-01-06 .

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