Abstract
This paper reviews the different aspects of the yield stress phenomenon and attempts a synthesis of knowledge. Yield stress can be probed using constant shear stress or shear rate. The magnitude of the result depends on the time allowed to determine whether the sample has developed continuous flow or has ceased flowing. It is closely associated with creep, stress growth and thixotropic breakdown and recovery, and the characteristic times of these transient responses play a part in yield stress measurement. In thixotropic fluids, yield stress is a function of structure and hence of time. In simple thixotropy, the yield stress derived from the equilibrium flow curve is the same as that for the fully built-up structure. But in many materials, the static yield stress obtained after prolonged rest is much higher than the dynamic yield stress from the equilibrium flow curve. This is associated with the phenomenon in which the equilibrium flow curve bends upwards as the shear rate is reduced to very low values. The paper also reviews the many methods that can be used to measure yield stress. It is pointed out that the choice of observation time or shear rate to use should be related to the characteristic time of the flow process to which the result is to be applied. Examples discussed are solids suspension capability of fluids, levelling and sagging, pipeline flow and start-up power requirement of mixers.
Abbreviations
- CS :
-
constant structure
- D :
-
diameter of Gun Rheometer tube
- EFC :
-
equilibrium flow curve
- G :
-
measured torque
- L :
-
length of Gun Rheometer tube
- P min :
-
minimum pressure to cause flow
- t :
-
time
- α :
-
form factor for shear stress
- β :
-
\( = (d\tau /dt)_{\dot \gamma } \)
- β y :
-
\( = (d\tau /dt)_{\dot \gamma = 0} \)
- \(\dot \gamma \) :
-
shear rate
- \(\dot \gamma _c \) :
-
a particular value of shear rate
- \(\dot \gamma _R \) :
-
reference shear rate
- \(\dot \gamma _T \) :
-
test shear rate
- τ :
-
shear stress
- τ y :
-
yield stress
- τ yd :
-
dynamic yield stress
- τ ys :
-
static yield stress
- 0:
-
initial value after speed change
- e :
-
equilibrium
References
Want FM et al. (1982) In: Proc. 8th Intern. Conf. Hydraul. Transp. Solids in Pipes, Paper E2, pp 249–262. Cranfield, Bedford: BHRA Fluid Engng
Keentok M, Milthorpe JF, O'Donovan E (1985) J Non-Newtonian Fluid Mech 17:23–35
Dealy JM (1984) J Rheol 28:181–195
Barnes HA, Walters K (1984) Rheol Acta 24:323–326
Cheng DC-H (1978) Bull Brit Soc Rheol 21:60–65
Sestak S, Houska M, Zitny R (1982) J Rheol 26:459–476
Buscall R et al. (1982) J Coll Interf Sci 85:78–86
Buscall R (1983) Shear flow and sedimentation behaviour of weakly flocculated suspensions. Paper to 3rd Australian Nat Cong Rheol, Melbourne, May
Cheng DC-H, Evans F (1965) Br J Appl Phys 16:1599–1617
Cheng DC-H (1971) The characterization of thixotropic behaviour. Stevenage: Warren Spring Laboratory, Report No LR 157 (MH)
Heywood NI (1984) The measurement of thixotropic properties. In: Training Course in Fluids Rheology, Course Manual, Lecture 12. Stevenage: Warren Spring Laboratory, Report No PRC 120 (MH); also in earlier course manuals
Cheng DC-H (1979) Measurement techniques for thixotropic properties. Paper to Brit. Ceramic Soc. Convention, York; Determination of bentonite-water dispersions. Paper to Joint British, Italian and Netherlands Societies of Rheology, Amsterdam 1979
Cheng DC-H, Richmond RA (1980) In: Astarita G, Marrucci G, Nicolais L (eds) Rheology, vol 2, Fluids. Plenum Pub. Corp., New York, pp 575–580
Davenport TC, Somper RSH (1971) J Inst Petrol 57:86–105
Cheng DC-H (1971) The behaviour of a cone-and-plate viscometer when used for loop experiments. Stevenage: Warren Spring Laboratory, 1973, Report No LR 178 (MH); J Phys E, Sci Instrum 4:693–699
Cheng DC-H (1971) The interpretation of the Ferranti-Shirley Viscometer data obtained on thixotropic fluids. Stevenage: Warren Spring Laboratory, Report No LR 158 (MH)
Broadman G, Whitmore RL (1961) Lab Pract 10:782–785
Zhukovskii SS, Gutkin AM (1966) Koll Zh 28:151–152. English translation: Coll J USSR 28: 127–128
Vocadlo JJ, Charles ME (1971) Canad J Chem Engng 49:576–582
Dinsdale A, Moore F (1962) Viscosity and its measurement. London, Chapman and Hall, pp 51–53
Mottram FJ (1961) Lab Pract 10:767–770
Sakharova MG et al. (1966) Lakokorasochnye Materialy i ikh Primeneuie 2:24–26 (English translation)
Gorazdovskii TYa, Rebinder PA (1970) Coll J USSR 32:425–432 (English translation)
Johnson KL (1970) J Mech Phys Solids 18:115–126
Onogi S, Masuda T, Matsumoto T (1970) Trans Soc Rheol 14:275–294
Komatsu H, Mitsui T, Onogi S (1972) Non-linear viscoelastic properties of semi-solid emulsions. Paper to 6th Intern Cong Rheol, Lyons. Summary in tome IV, p 137–139
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Cheng, D.CH. Yield stress: A time-dependent property and how to measure it. Rheol Acta 25, 542–554 (1986). https://doi.org/10.1007/BF01774406
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DOI: https://doi.org/10.1007/BF01774406