An Experimental Technique for the Dynamic Characterization of Soft Complex Materials

We describe an experimental technique to study the dynamic behavior of complex soft materials, based on high-speed microscopic imaging and direct measurements of dynamic forces and deformations. The setup includes high sensitivity dynamic displacement measurements based on geometric moiré interferometry and high-speed imaging for in-situ, full-field visualization of the complex micro-scale dynamic deformations. The method allows extracting dynamic stress-strain profiles both from the moiré interferometry and from the high-speed microscopic imaging. We discuss the advantages of using these two complementing components concurrently. We use this technique to study the dynamic response of vertically aligned carbon nanotube foams subjected to impact loadings at variable deformation rates. The same technique can be used to study other micro-structured materials and complex hierarchical structures.