Factors Affecting Elasticity
For isotropic materials, the presence of fractures affects the Young and the shear modulus perpendicular to the planes of the cracks, which decrease (Young's modulus faster than the shear modulus) as the fracture density increases, indicating that the presence of cracks makes bodies brittler. Microscopically, the stress-strain relationship of materials is in general governed by the Helmholtz free energy, a thermodynamic quantity. Molecules settle in the configuration which minimizes the free energy, subject to constraints derived from their structure, and, depending on whether the energy or the entropy term dominates the free energy, materials can broadly be classified as energy-elastic and entropy-elastic. As such, microscopic factors affecting the free energy, such as the equilibriumdistance between molecules, can affect the elasticity of materials: for instance, in inorganic materials, as the equilibrium distance between molecules at 0 K increases, the bulk modulus decreases. The effect of temperature on elasticity is difficult to isolate, because it there are numerous factors affecting it. For instance, the bulk modulus of a material is dependent on the form of its lattice, its behavior under expansion, as well as the vibrations of the molecules, all of which are dependent on temperature.
Read more about this topic: Elasticity (physics)
Famous quotes containing the words factors, affecting and/or elasticity:
“Girls tend to attribute their failures to factors such as lack of ability, while boys tend to attribute failure to specific factors, including teachers’ attitudes. Moreover, girls avoid situations in which failure is likely, whereas boys approach such situations as a challenge, indicating that failure differentially affects self-esteem.”
—Michael Lewis (late–20th-century)
“It is so manifestly incompatible with those precautions for our peace and safety, which all the great powers habitually observe and enforce in matters affecting them, that a shorter water way between our eastern and western seaboards should be dominated by any European government, that we may confidently expect that such a purpose will not be entertained by any friendly power.”
—Benjamin Harrison (1833–1901)
“A submissive spirit might be patient, a strong understanding would supply resolution, but here was something more; here was that elasticity of mind, that disposition to be comforted, that power of turning readily from evil to good, and of finding employment which carried her out of herself, which was from Nature alone. It was the choicest gift of heaven.”
—Jane Austen (1775–1817)