Sage-Tips

What are shear thickening fluids used for?

For ballistic applications, fabrics are treated with shear thickening fluids (STFs) to improve the impact resistance of the fabric to be used as soft body armor. Generally, high-performance fibers like p-amide (e.g., Kevlar®), ultrahigh molecular weight polyethylene (UHMWPE) (e.g., Spectra®) etc.

What are some examples of shear thickening fluids?

A common example of shear thickening fluids is a mixture of cornstarch and water. You have probably seen examples of this on TV or the internet, where people can run over this kind of solutions and yet, they will sink if they stand still. Fluids are shear thinning if the viscosity decreases as the shear rate increases.

Which fluid is shear thickening?

Shear thickening fluid (STF) occurs in dispersions of highly condensed colloid particles and is categorized as a non-Newtonian fluid whose viscosity increases under shear loading which makes them beneficial in protective and impact resistance applications.

What is shear thickening and how does it work?

Shear thickening behavior occurs when a colloidal suspension transitions from a stable state to a state of flocculation. A large portion of the properties of these systems are due to the surface chemistry of particles in dispersion, known as colloids. The opposite of a dilatant material is a pseudoplastic.

What is the difference between shear thinning and shear thickening?

Shear thinning is a phenomenon characteristic of some non-Newtonian fluids in which the fluid viscosity decreases with increasing shear stress. Shear thickening is the opposite phenomenon. (By contrast to both, viscosity in Newtonian fluids is by definition independent of the forces exerted on the fluid.)

What is dilatant used for?

Potential Applications of Dilatants: Shock absorption Systems. Automotive Suspension – Magnetic particles suspended. Impact Stress Cushioning – Sport / Athletics.

What is the difference between viscosity and rheology?

The key difference between rheology and viscosity is that rheology is the study of the flow of matter, whereas viscosity is a measure of its resistance to deformation. Rheology is a branch of physics or physical chemistry, while viscosity is a quantitative measurement that is useful in chemistry.

Is motor oil a shear thickening fluid?

Fluids that exhibit shear thinning are sometimes called pseudoplastics and are typically complex fluids such as blood, motor oil, ketchup, and even whipped cream, though simple fluids can also exhibit the behavior near their critical point (ex: xenon in Ref. 1).

What is the difference between dilatant and pseudoplastic fluids?

1.1 Time-Independent Non-Newtonian Fluids. These are fluids in which the viscosity does not depend on fluid shear stress rate history. An example of dilatant fluid is sand in water. On the other hand, when viscosity decreases when stress increases, the fluid is called pseudoplastic fluid.

Is honey a dilatant fluid?

Water and honey are both Newtonian fluids, though honey is much more viscous than water. Dilatant fluids, also known as shear thickening fluids, are those in which the apparent viscosity increases as the shear rate increases.