On behavior of the thixotropic fluids

The Effect of Elastic Modulus Rate in Stress Controlled Tests on the Modified Jeffrey’s Model for Structured Fluids

“…The initial condition in all tests is of a relaxed ( 0 τ = for 0 t < ), at rest ( 0 γ = for 0 t < ) and fully structured material ( 0 λ λ = for 0 t < ). According to Souza Mendes and Thompson [15], the results are presented in the dimensionless form. The set of parameters used are: 0,5 n = ; / 2 y yd τ τ = ; One can note that, initially, the shear rate decreases until a constant value is attained, which indicates that the material is nearly at rest.…”

“…Several types of constitutive equations can be found in the specialized literature. It is important point out that the older models [6,8,10] are based on equations derived from viscoplastic models, however in the recent constitutive models [1,4,9,[11][12][13][14][15] the elastic effect was included. The elastic effect showed an expressive contribution in both terms (building up/breakdown) of the evolutionary equation of the structural parameter.…”

“…In this context, some constitutive models from the linear viscoelastic theory has been directly used to structured materials modeling [12][13][14][15]. In this sense, two types of models have been highlighted in the specialized literature due to simplicity of the mathematical expressions and easy computational implementation: Maxwell (spring element in series with a damp element) and Jeffrey's (a Maxwellian element in parallel with a damp element) models [16].…”

Optimization of mechanical properties of Al-metal matrix composite produced by direct fusion of beverage cans

“…Metallic alloys, and thus aluminum alloys, display a thixotropic behavior when processed in a semi-solid state. This characteristic of viscoelastic fluids results in an apparent viscosity decrease when a shear rate is applied to the fluid; the apparent viscosity is reduced to a constant value sometime after the shear rate is applied [14]. Thus, the observed difference in size and distribution of the secondary phases in the Al-MMC microstructure produced at different shear rates can be attributed to their thixotropic behavior: when the viscosity of the semi-solid bath varies according to the applied shear rate, this affects the mass transfer during continuous cooling (and solidification of the Al-MMC).…”

Towards the Development of a Strategy to Characterize and Model the Rheological Behavior of Filled, Uncured Rubber Compounds

“…Population Balance Models (PBMs) take into account the flow-induced changes of the microstructure and describe how these changes influence the bulk rheology of the material. In the last years, there has been a growing interest in developing thixotropic constitutive models from PBMs [ 33 , 34 ].…”