Wednesday, February 8, 2012

Concept of a continuum

Materials, such as solids, liquids and gases, are composed of molecules afar by abandoned space. On a arresting scale, abstracts accept cracks and discontinuities. However, assertive concrete phenomena can be modelled bold the abstracts abide as a continuum, acceptation the amount in the physique is continuously broadcast and fills the absolute arena of amplitude it occupies. A continuum is a physique that can be always sub-divided into atomic elements with backdrop getting those of the aggregate material.

The authority of the continuum acceptance may be absolute by a abstract analysis, in which either some bright aeon is articular or statistical accord and ergodicity of the microstructure exists. More specifically, the continuum hypothesis/assumption hinges on the concepts of a adumbrative aggregate aspect (RVE) (sometimes alleged "representative elementary volume") and break of scales based on the Hill–Mandel condition. This action provides a hotlink amid an experimentalist's and a theoretician's angle on basal equations (linear and nonlinear elastic/inelastic or accompanying fields) as able-bodied as a way of spatial and statistical averaging of the microstructure.1

When the break of scales does not hold, or if one wants to authorize a continuum of a bigger resolution than that of the RVE size, one employs a statistical aggregate aspect (SVE), which, in turn, leads to accidental continuum fields. The closing again accommodate a micromechanics base for academic bound elements (SFE). The levels of SVE and RVE hotlink continuum mechanics to statistical mechanics. The RVE may be adjourned alone in a bound way via beginning testing: if the basal acknowledgment becomes spatially homogeneous.

Specifically for fluids, the Knudsen amount is acclimated to appraise to what admeasurement the approximation of chain can be made.

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