Tham khảo tài liệu 'friction, lubrication, and wear technology (1997) part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | p TịU Note This number is normally written as ZN p in which Z denotes the dynamic viscosity Nthe frequency of rotation andp the pressure Ref 1 . See also Ocvirk number Sommerfeld number and Stribeck curve . Hertzian contact area 1 The contact area also diameter or radius of contact between two bodies calculated according to Hertz s equations of elastic deformation Ref 1m . 2 The apparent area of contact between two nonconforming solid bodies pressed against each other as calculated from Hertz s equations of elastic deformation Ref 2 . Hertzian contact pressure 1 The pressure at a contact between two solid bodies calculated according to Hertz s equations of elastic deformation Ref 1 . 2 The magnitude of the pressure at any specified location in a Hertzian contact area as calculated from Hertz s equations of elastic deformation Ref 2 . high-stress abrasion A form of abrasion in which relatively large cutting forces are imposed on the particles or protuberances causing the abrasion and that produces significant cutting and deformation of the wearing surface. Note In metals high-stress abrasion can result in significant surface strain hardening. This form of abrasion is common in mining and agricultural equipment and in highly loaded bearings where hard particles are trapped between mating surfaces Ref 3m . See also low-stress abrasion . highly deformed layer In tribology a layer of severely plastically deformed material that results from the shear stresses imposed on that region during sliding contact. See also Beilby layer and white layer . Hohman A-6 wear machine A widely used type of wear and friction testing machine in which a rotating ring specimen is squeezed between two diametrically opposed rub blocks. Note This design is said to eliminate shaft flexure such as that found in other machines whose load application from the rub block to the ring is from one side only. Block geometry can be changed from flat to conforming or V-block. This type of machine is .