shear-thickening

Stress-induced thickening

Shear-thickening describes fluids that become more viscous when force is applied.

A mixture of cornstarch and water flows easily when stirred slowly but resists rapid movement—you can run across a pool of it without sinking.

The opposite of shear-thinning.

Also called dilatant.

rheology

non-Newtonian

Viscosity changes with stress

viscoelasticityCombined fluid-solid deformation behavior
deformationChange in shape
stress-strainMaterial response relationship

applications

body armor

Protective garment stopping bullets

KevlarProtective synthetic fiber
bulletproof vestsProtective garments resisting gunfire
protective gearEquipment preventing bodily harm

impact protection · shock absorption · helmets · dampers · smart materials · puncture-resistant · vehicle armor · industrial safety

mechanism

viscosity

Fluid's flow resistance

suspensionTemporary halt or exclusion
microstructureSubmillimeter material composition
concentrationSustained single-minded attention

stress response · fluid dynamics · discontinuous

examples

oobleck

Cornstarch-water suspension

cornstarchMaize-derived thickening powder
polyethylene glycolWaxy synthetic polymer chain
quicksandYielding, engulfing sediment

wet sand · custard

Opposites

rheological response to shear stress

shear-thickeningNewtonian

Of classical mechanics

viscosity state

shear-thickeningthinning

Reducing density or number

thin · runny · watery · free-flowing · liquefying

Family

shear, thickening, shears, sheared, shearing, shearer, thick, thicken, thickens

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