Shear straining at different velocities, including high and very high
strain rates, is discussed. Some experimental techniques which allows
for experiments at high and very high strain rates are briefly reviewe
d. A new experimental technique based on direct impact on Modified Dou
ble Shear a specimen (MDS) is also reviewed. A one-dimensional model f
or simple shear is applied together with a constitutive relation which
takes into account rate and temperature sensitivity a generalised con
dition for instability of adiabatic shearing at different rates has be
en derived and discussed. Finally, an analysis of deformation trapping
in shear due to thermoplastic instability in one-dimensional plastic
wave propagation is analysed. The critical impact velocity in shear is
analysed in detail and values are compared with preliminary experimen
ts.