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Poisson's ratio of a material defines the ratio of transverse strain (x direction) to the axial strain (y direction)In materials science and solid mechanics, Poisson's ratio (symbol: ν ()) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading.
In general there are two models, one for axial loading (Voigt model), [2] [4] and one for transverse loading (Reuss model). [2] [5] In general, for some material property (often the elastic modulus [1]), the rule of mixtures states that the overall property in the direction parallel to the fibers may be as high as
Axial loading is defined as applying a force on a structure directly along a given axis of said structure. [1] In the medical field, the term refers to the application of weight or force along the course of the long axis of the body. [2] The application of an axial load on the human spine can result in vertebral compression fractures. [3]
The methods employed to predict the response of a structure under loading and its susceptibility to various failure modes takes into account the properties of the materials such as its yield strength, ultimate strength, Young's modulus, and Poisson's ratio. In addition, the mechanical element's macroscopic properties (geometric properties) such ...
As examples, in PF 5 the axial P−F bond length is 158 pm and the equatorial is 152 pm, and in PCl 5 the axial and equatorial are 214 and 202 pm respectively. [ 2 ] In the mixed halide PF 3 Cl 2 the chlorines occupy two of the equatorial positions, [ 2 ] indicating that fluorine has a greater apicophilicity or tendency to occupy an axial position.
This is the case, for example, in a portion of liquid or gas at rest, whether enclosed in some container or as part of a larger mass of fluid; or inside a cube of elastic material that is being pressed or pulled on all six faces by equal perpendicular forces — provided, in both cases, that the material is homogeneous, without built-in stress ...
For example, the tert-butyl group (A-value=4.9) has a larger A-value than the trimethylsilyl group (A-value=2.5), yet the tert-butyl group actually occupies less space. This difference can be attributed to the longer length of the carbon–silicon bond as compared to the carbon–carbon bond of the tert -butyl group.
An example is cyclopropane which, because of its planar geometry, has six fully eclipsed carbon and axial hydrogen bonds making the strain 116 kJ/mol (27.7 kcal/mol). [5] Strain can also be decreased when the carbon-carbon bond angles are close or at the preferred bond angle of 109.5°, meaning a ring having six tetrahedral carbons is typically ...