Dilatancy may refer to:
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Dilatancy (granular material)
In soil mechanics, dilatancy or shear dilatancy is the volume change observed in granular materials when they are subjected to shearing (physics), shear deformations. This effect was first described scientifically by Osborne Reynolds in 1885/188 ...
: an increase in volume under shear
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Dilatancy (viscous material): the solidification of viscous fluids under pressure
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