When two objects touch, only a certain portion of their surface areas will be in contact with each other. This area of true contact, most often constitutes only a very small fraction of the apparent or nominal contact area. In relation to two contacting objects, the contact area is the part of the nominal area that consists of atoms of one object in true contact with the atoms of the other object. Because objects are never perfectly flat due to asperities, the actual contact area (on a microscopic scale) is usually much less than the contact area apparent on a macroscopic scale. Contact area may depend on the normal force between the two objects due to deformation. [1]
The contact area depends on the geometry of the contacting bodies, the load, and the material properties. The contact area between the two parallel cylinders is a narrow rectangle. Two, non-parallel cylinders have an elliptical contact area, unless the cylinders are crossed at 90 degrees, in which case they have a circular contact area. Two spheres also have a circular contact area.
One way of determining the actual contact area is to determine it indirectly through a physical process that depends on contact area. For example, the resistance of a wire is dependent on the cross-sectional area, so one may find the contact area of a metal by measuring the current that flows through that area (through the surface of an electrode to another electrode, for example.)
^Zhai, C.; Hanaor, D.; Proust, G.; Gan, Y. (2015). "Stress-Dependent Electrical Contact Resistance at Fractal Rough Surfaces". Journal of Engineering Mechanics. 143 (3): B4015001. doi:10.1061/(ASCE)EM.1943-7889.0000967.
April 08, 2024
contact, area, when, objects, touch, only, certain, portion, their, surface, areas, will, contact, with, each, other, this, area, true, contact, most, often, constitutes, only, very, small, fraction, apparent, nominal, contact, area, relation, contacting, obje. When two objects touch only a certain portion of their surface areas will be in contact with each other This area of true contact most often constitutes only a very small fraction of the apparent or nominal contact area In relation to two contacting objects the contact area is the part of the nominal area that consists of atoms of one object in true contact with the atoms of the other object Because objects are never perfectly flat due to asperities the actual contact area on a microscopic scale is usually much less than the contact area apparent on a macroscopic scale Contact area may depend on the normal force between the two objects due to deformation 1 The contact area depends on the geometry of the contacting bodies the load and the material properties The contact area between the two parallel cylinders is a narrow rectangle Two non parallel cylinders have an elliptical contact area unless the cylinders are crossed at 90 degrees in which case they have a circular contact area Two spheres also have a circular contact area Contents 1 Friction and contact area 2 Methods for determining contact area 3 See also 4 ReferencesFriction and contact area editIt is an empirical fact for many materials that F mN where F is the frictional force for sliding friction m is the coefficient of friction and N is the normal force There isn t a simple derivation for sliding friction s independence from area Methods for determining contact area editOne way of determining the actual contact area is to determine it indirectly through a physical process that depends on contact area For example the resistance of a wire is dependent on the cross sectional area so one may find the contact area of a metal by measuring the current that flows through that area through the surface of an electrode to another electrode for example See also editContact mechanics Contact resistanceReferences edit Zhai C Hanaor D Proust G Gan Y 2015 Stress Dependent Electrical Contact Resistance at Fractal Rough Surfaces Journal of Engineering Mechanics 143 3 B4015001 doi 10 1061 ASCE EM 1943 7889 0000967 Retrieved from https en wikipedia org w index php title Contact area amp oldid 1167625847, wikipedia, wiki, book, books, library,
