Materials such as biological materials, glasses, polymers, and some metals exhibit significant time dependency with respect to mechanical properties. This viscoelasticity makes it difficult to completely describe the material response using traditional nanoindentation techniques. Building upon traditional dynamic mechanical analysis theory (DMA), Bruker has established its nanoDynamic Mode option for the in-situ mechanical analysis of nanoscale materials.
nanoDynamic Mode offers several testing modes in which an oscillating force is applied to a sample and the resultant displacement amplitude and phase shift are measured using a lock-in amplifier. Using this technique, the contact stiffness and damping properties of the material can be accurately determined, allowing for the measurement of storage (E’) and loss (E’’) moduli, as well as tan delta. Additionally, this technique has been expanded to include additional testing modes for characterizing creep and inducing fatigue in a wide variety of materials or structures while deformation is simultaneously monitored with the electron microscope.