Asperity

Asperity

Asperity is defined as unevenness of surface, roughness, ruggedness (OED). Flat surfaces, even those polished to a mirror finish, are not truly flat on an atomic scale. They are rough, with sharp, rough or rugged outgrowth, termed asperities.

When two macroscopically flat surfaces come into contact, initially they only touch at a few of these asperity points. These cover only a very small portion of the surface area. Friction and wear originate at these points and thus understanding their behavior is important when studying materials in contact. When the surfaces are subjected to a compressive load, the asperities plastically deform, increasing the contact area between the two surfaces until the contact area is sufficient to support the load.

The Archard equation is a simplified model of asperity deformation when materials in contact are subject to a force.

ee also

Naturally occurring earthquakes

References

External links


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  • Asperity — As*per i*ty, n.; pl. {Asperities}. [L. asperitas, fr. asper rough: cf. F. asp[ e]rit[ e].] 1. Roughness of surface; unevenness; opposed to {smoothness}. The asperities of dry bodies. Boyle. [1913 Webster] 2. Roughness or harshness of sound; that… …   The Collaborative International Dictionary of English

  • asperity — index rigor, severity Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • asperity — c.1200, asprete hardship, harshness of feelings, a figurative use, from O.Fr. asperité difficulty, painful situation, harsh treatment (12c., Mod.Fr. ápreté), from L. asperitatem (nom. asperitas) roughness, from asper rough, harsh, of unknown… …   Etymology dictionary

  • asperity — *acrimony, acerbity Analogous words: sharpness, keenness (see corresponding adjectives at SHARP): causticity, mordancy (see corresponding adjectives at CAUSTIC): snappishness, waspishness, irritability (see corresponding adjectives at IRRITABLE)… …   New Dictionary of Synonyms

  • asperity — [n] harshness; bad temper acerbity, acrimony, bitterness, churlishness, crabbiness, crossness, difficulty, disagreeableness, irascibility, irritability, meanness, moroseness, peevishness, roughness, sharpness, sourness, sullenness, tartness;… …   New thesaurus

  • asperity — ► NOUN (pl. asperities) 1) harshness of tone or manner. 2) a rough edge on a surface. ORIGIN Latin asperitas, from asper rough …   English terms dictionary

  • asperity — [ə sper′ə tē] n. pl. asperities [ME & OFr asprete < L asperitas, roughness < asper, rough < IE * apo spero , repellent < base * apo , away + * sper , to flick away, push] 1. roughness or harshness, as of surface, sound, weather, etc.… …   English World dictionary

  • asperity — noun a) Roughness as of stone or weather. Asperity of Maines winter b) Something that is harsh and hard to endure. Go, ribald, get you henceTo your cabin with celerity.This is the consequenceOf ill advised asperity! …   Wiktionary

  • asperity — [[t]æspe̱rɪti[/t]] N UNCOUNT: oft with N If you say something with asperity, you say it impatiently and severely. [FORMAL] I told you Preskel had no idea, remarked Kemp with some asperity. Syn: sharpness …   English dictionary

  • asperity — noun (plural ties) Etymology: Middle English asprete, from Anglo French aspreté, from aspre rough, from Latin asper, from Old Latin *absperos, from ab ab + speros; akin to Sanskrit apasphura repelling, Latin spernere to spurn more at spurn Date:… …   New Collegiate Dictionary

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