Gap loading conditions

Sample inertial forces will be small if the sample density, p, is small compared with G /h f or (G"/h f ) where h is the shearing gap thiek-ness and / is the frequency of oscillation (in Hz). Under these eonditions, the states of stress or strain may be eonsidered uniform throughout the shearing gap and to experienee no periodie spatial variation. This represents the gap loading condition [Ferry, 1980]. 

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