Strain rate dependence of indentation hardness has been widely used to study time-dependent plasticity. However, the currently available techniques limit the range of strain rates that can be achieved during indentation testing. Recent advances in electronics have enabled nanomechanical measurements with very low noise levels (sub nanometer) at fast time constants (20 µs) and high data acquisit...

Attractive colloidal particles are trapped in metastable states such as colloidal gels at high attraction strengths and attractive glasses and high volume fractions. Under shear such states flow via a two step yielding process that relates to bond and cluster or cage breaking. We discuss the way the structural properties and related stress response are affected by the shear rate. At low rates c...

Experimental investigation and numerical simulation of the influence of the strain rate in laser forming are presented. To isolate and effectively study the strain rate effects, which are temperature dependent, a "constant peak temperature" method is developed with the aid of numerical modeling and solution. Under the condition of the constant peak temperature, the effects of strain rate on for...

The high strain rate behavior of two cellular materials was investigated using a quasi-static loading stage and a Kolsky bar apparatus. The yield stress of these core materials under dynamic loading was found higher than in quasi-static loading. However, the plateau stress after yielding is not so sensitive to strain rate. For Aluminum foam materials, the deformation was more localized for quas...

Gas guns and velocity interferometric techniques have been used to determine the loading behavior of AD995 alumina rods 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstr...