Analysis of Impact Specimens at the Nanoscale

In recent years there has been much interest in the application of polymer materials at the micro- and nanoscale as microelectronic devices are made smaller and smaller. Constantinides describes an analysis and experiments of materials at the nanoscale. An instrumented pendulum device with a diamond Berkovich indenter was used to indent polymer specimens at a rate of 0.7-1.5 mm/s. The highest impact velocity (1.5 mm/s) corresponded to an impulse energy of 250 nJ. (The Berkovich nanoindenter similar to the Vickers type is normally used for testing the hardness of a material. It has a three-sided pyramid shape. It has also 

Thin films of materials tested included two semi-crystalline polymers PE and PP above their corresponding glass transition temperatures Tg, and three fully amorphous polymers PS, PC, and PMMA well below The authors concluded The maximum penetration depth jc ax was found to scale linearly with the residual depth X, for all six polymers, irrespective of material strain rate sensitivity. The ratio Ix is related directly to the ratio of total impact energy W IW dissipated via an elastic deformation of the material. 

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