1、BRITISH STANDARD BS 5168:1975 Glossary of Rheological terms UDC 001.4:532.135BS5168:1975 This British Standard, having been endorsed by the Chairmanofthe Chemical Divisional Council, was publishedunder the authority ofthe Executive Board on 30 May1975 BSI 11-1999 The following BSI references relate
2、to the work on this standard: Committee reference C/41 Draft for comment72/54972 DC ISBN 0 580 08540 6 Co-operating organization British Society of Rheology NOTEThe members of the Technical Committee responsible for the preparation of this BritishStandard were all nominated by the British Society of
3、 Rheology but their combined experience was representative of the following other sciences and industries: applied mathematics biblogy building science fluid mechanics food science metallurgy paint petroleum plastics. Amendments issued since publication Amd. No. Date of issue CommentsBS5168:1975 BSI
4、 11-1999 i Contents Page Co-operating organization Inside front cover Foreword iiBS5168:1975 ii BSI 11-1999 Foreword The term rheology was defined as “the science of the deformation and flow of matter” at the inaugural meeting of the (American) Society of Rheology in Washington, D.C. in1929. This de
5、finition has been used as a guide in the selection of terms for inclusion in this glossary. In the ensuing forty years, many new phenomena have been discovered and new technical terms have been required. The council of the British Society of Rheology approached the BritishStandards Institution in or
6、der that a British Standard glossary might be drawn up. In compiling this glossary the following guidelines have been adopted: a) Terms used in other disciplines that can be found in general technical dictionaries have usually been omitted. b) Mathematical equations have been used only where it was
7、unavoidable. c) Definitions have been prepared so as to retain the rheological significance of the term while being compatible with the usage in as many other disiplines as possible. Use was made of the following publications in the preparation of this glossary. REINER, M. and SCOTT BLAIR, G. W., Rh
8、eological terminology. Chapter9 in “Rheology; theory and applications”. (ed.) EIRICH, F. R., vol.4. Academic PressInc.,1967. STANDARDS ASSOCIATION OF AUSTRALIA. Glossary of terms and classification of properties relating to the deformation and flow of materials,1970. AustralianStandardZ61:1970. LE C
9、ONSEIL DU GROUPE FRANAIS DE RHOLOGIE. Dictionnaire Rhologique, Socit de Diffusion des Techniques du Batiment et des Travaux Publics,1968. The terms in this glossary have been listed in alphabetical order. Where a number of terms share the same definition the preferred term is listed first in bold ty
10、pe with the alternative terms in smaller type underneath it. Thealternative term also appears alphabetically in the list, also in smaller type. These alternative terms are not deprecated unless this is stated beside the term. Where alternative terms have been considered to be of equal merit they hav
11、e been defined separately. Terms used in definitions that are also defined in this glossary are printed in italics. NOTEGeneral cross references to related terms have been given under the following terms: model modulus viscosity. A British Standard does not purport to include all the necessary provi
12、sions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to15 and a
13、back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS5168:1975 BSI 11-1999 1 Term Definition activation energy The additional energy which molecules require above their aver
14、age kinetic energy in order to permit a particular process to occur. adhesion The force that resists the separation of two bodies in contact. aggregate A group of particles held together in clumps. anelasticity See delayed elasticity. angle of extinction The smallest angle between the streamlines an
15、d an optic axis of a birefringent flowing liquid (see flow birefringence). The optic axis is determined by maximum light extinction. angle of isocline A right angle minus the angle of extinction. angle of repose 1. The maximum angle between the surface of a heap of loosely piled material and the hor
16、izontal. 2. The maximum angle at which a plane can be inclined before a solid body resting on it will move by either rolling or sliding. anisotropic Not having the same properties in all directions. annealing Heat treatment with the aim of reducing internal stress. anti-thixotropy See negative thixo
17、tropy. apparent viscosity The quotient of shear stress divided by rate of shear when this quotient is dependent on the rate of shear. areal viscosity The property of an interface to resist increasingly an isotropic change in area with increase in the rate of change. Barus effect See die swell. Bausc
18、hinger effect The lowering of the elastic modulus in a hysteresis experiment following the reversal of the applied stress, which produced plastic deformation. Bingham model Bingham body, deprecated A model with the behaviour of an elastic solid up to the yield stress; above the yield stress the rate
19、 of shear is directly proportional to the shear stress minus the yield stress. body 1. A subjective assessment of consistency. 2. See model; this use is deprecated, e.g.Bingham body. body force A force that acts through the whole volume of the system. Boltzmanns linear superposition principle The as
20、sumption that responses are additive, e.g.that the stress resulting from the sum of several deformations, each a function of time, is the sum of the stresses resulting from the separate deformations. brittle fracture A fracture under conditions of little or no previous plastic deformation. bulk modu
21、lus The quotient of the isotropic stress divided by the elastic volume strain. The reciprocal of compressibility (2). bulk viscosity volume viscosity The viscosity (2) associated with changes in volume, i.e.the quotient of isotropic stress divided by volume strain rate. Burgers model A combination o
22、f a Kelvin model and a Maxwell model in series. Cauchy strain engineering strain The ratio of a linear extension to the original length.BS5168:1975 2 BSI 11-1999 Term Definition chemorheology The study of time-dependent phenomena in flow behaviour resulting from chemical changes. Examples are the sh
23、ear (1) degradation and cross-linking of polymers. circular Couette flow Shear flow in the annulus between two co-axial cylinders in relative rotation; often used without the adjective circular (see Couette flow and plane Couette flow). coefficient of cross-viscosity The second order normal stress c
24、oefficient of a Reiner-Rivlin fluid model. Strictly not a viscosity. coefficient of fluidity The reciprocal of the coefficient of dynamic viscosity (1). coefficient of friction The ratio of the frictional force to the normal load between solid bodies. coefficient of interfacial viscosity The constan
25、t value of the quotient of the force per unit length acting along a line lying in the plane of the interface divided by the rate of shear in the plane of the interface for steady flow. Its dimensions are the same as those of viscosity times length. coefficient of viscosity The constant value of the
26、quotient of the shear stress divided by the rate of shear for steady flow characteristic of Newtonian fluid model behaviour commonly referred to as viscosity (2) or dynamic viscosity (1), compare apparent viscosity. coefficient of viscous traction The constant value of the quotient of the tensile st
27、ress divided by the rate of extension applied for Newtonian fluid model behaviour. cohesion The attraction between the molecules forming the mass of a liquid or a solid. complex compliance The mathematical representation of a compliance as being the sum of a real and an imaginary part. The real part
28、 is sometimes called storage compliance and the imaginary part loss compliance. complex modulus dynamic modulus The mathematical representation of a modulus as being the sum of a real and an imaginary part. The real part is sometimes called storage modulus and the imaginary part loss modulus. comple
29、x viscosity The mathematical representation of a viscosity (2) as being the sum of a real and an imaginary part. The real part is usually called dynamic viscosity (2), the imaginary part is related to the real part of the complex modulus. compliance The quotient of strain divided by its correspondin
30、g stress. The reciprocal of elastic modulus. compressibility 1. The relative volume decrease caused by an increase of pressure. 2. The reciprocal of bulk modulus. consistency A general term for the property of a material by which it resists permanent change of shape. constitutive equation equation o
31、f state rheological equation An equation relating stress, strain, time and sometimes other variables, such as temperature. Also called rheological equation of state. continuum rheology The rheology that treats a material as a continuum without explicit consideration of microstructure. Also called ma
32、crorheology and phenomenological rheology. Couette flow Shear flow in the annulus between two co-axial cylinders in relative rotation. Also called circular Couette flow. (See plane Couette flow.)BS5168:1975 BSI 11-1999 3 Term Definition creaming The rising to the surface of particles of a dispersed
33、phase in a liquid. creep The slow deformation of a material; usually measured under constant stress. (See also primary creep, secondary creep and tertiary creep.) creep function A function relating deformation to time, when a unit stress is applied instantaneously at zero time and kept constant ther
34、eafter. cross-viscosity See coefficient of cross-viscosity. Darcy friction factor See friction factor. dashpot A model for viscous flow, typically represented by a piston moving in a cylinder of liquid, usually representing Newtonian fluid model behaviour. Deborah number 1. The ratio of a relaxation
35、 time of a material to the duration of the observation. 2. The ratio of a time characteristic of a material to a characteristic time of observation. deformation A change of shape or volume or both. delayed elasticity anelasticity A reversible but a time-dependent deformation. deviator See extra stre
36、ss tensor. die swell Barus effect Merrington effect A post-extrusion swelling. differential viscosity The derivative of stress with respect to the rate of deformation in simple shear. dilatancy 1. The increase in volume caused by shear (1). 2. Sometimes used as synonymous with shear thickening (depr
37、ecated). ductility The extent of irreversible plastic strain at fracture. dynamic modulus See complex modulus. dynamic recovery A recovery from internal stress. dynamic viscosity 1. A synonym of coefficient of viscosity used to distinguish this quantity from kinematic viscosity. The reciprocal of fl
38、uidity. 2. The quotient of the part of the stress in phase with the rate of strain divided by the rate of strain under sinusoidal straining. elastic The adjective for elasticity. elastic after-effect The delay, caused by viscous forces, in the establishment of a recovery from an elastic strain. elas
39、tic fore-effect A time-delayed elastic deformation under stress. elasticity A reversible stress/strain behaviour. elastic energy See strain energy. elastic limit The point on the stress/strain curve at which plastic deformation commences; specifiable in terms of either stress or strain. elastic liqu
40、id elasticoviscous liquid elastoviscous liquid A liquid showing elastic as well as viscous properties on shearing (see elasticoviscous and viscoelasticity).BS5168:1975 4 BSI 11-1999 Term Definition elastic modulus modulus of elasticity The quotient of a stress divided by the corresponding elastic st
41、rain (see bulk modulus, shear modulus and Youngs modulus). The reciprocal of compliance. elasticoplastic material elastic plastic material A plastic material showing some elasticity. elasticoviscous liquid See elastic liquid. elasticoviscous A descriptive term for a liquid having both viscous and el
42、astic properties. elastic turbulence A disturbance produced as a result of elasticoviscous behaviour. An example of this is melt fracture. elastoviscous liquid See elastic liquid. electroviscous effect Electrical effects influencing viscosity: (a) caused by charged particles in suspension; (b) cause
43、d by the application of an external electric field. elongational viscosity Trouton viscosity The quotient of the tensile stress divided by the rate of extension. engineering strain See Cauchy strain. endurance See fatigue life. endurance limit See fatigue strength. equation of state See constitutive
44、 equation and rheological equation of state. extrapolated shear stress The intercept on the stress axis of the extrapolation of the upper, linear part of a flow curve. extra stress tensor deviator The difference between the stress tensor and the isotropic pressure contribution; used for incompressib
45、le materials. false body A descriptive term used for the following: (a) pseudoplasticity; (b) thixotropy. Fanning friction factor See friction factor. fatigue life endurance The number of stress cycles either at constant stress amplitude or at constant strain amplitude leading to failure. fatigue li
46、mit The highest value, of either stress or strain amplitude, applied indefinitely(1 to5 million cycles in practice) that will not lead to failure. fatigue strength endurance limit The value of either the stress amplitude or the strain amplitude at which the test specimen would have a life of a given
47、 number of cycles. flow A deformation, of which at least part is non-recoverable (rheological use of the term). flow birefringence The optical anisotropy caused by flow. flow curve A curve relating stress to rate of shear. flow elasticity The ability of a liquid to recover part of its deformation in
48、duced by flow. flow stress The lowest stress, in tension or shear (1), necessary to induce plastic flow in a material.BS5168:1975 BSI 11-1999 5 Term Definition fluid A liquid or a gas. fluidity The reciprocal of dynamic viscosity (1). friction See coefficient of friction. friction factor In flow thr
49、ough a pipe the shear stress at the wall divided by the kinetic energy of the flow per unit volume. In laminar flow it equals64/Re, if the Reynolds number (Re) relates to the hydraulic radius of the pipe (Darcy friction factor), and it equals16/Re if the Reynolds number relates to the actual radius of the pipe (Fanning friction factor). In turbulent flow the friction factor varies very little with the Reynolds number but is strongly dependent on the relative roughness of the wall. frozen-in stress See residual stress. frozen stress See residual stress. glide A plastic
