Micro-systems for micro and nano-mechanical testing

This thesis addresses the design and optimization of MEMS devices for nanoscale material experiments. The testing systems are designed to characterize one-dimensional materials, primarily single crystal nano-wires, at high strain rate (from 10^3 1/s to 10^5 1/s), in pure tensile behavior. Two different devices have been studied and developed. For both of them, analytical computations have been done in static and dynamic regime, followed by multi-physics FEM simulations. The first one is composed by a piezoelectric actuator on one side and a particular capacitive displacement transducer on the other side, with a specimen in between. The second one consists of two capacitive elements one to impose the force, one to measure the displacement, the specimen is fixed on a standing side. This MEMS device, for mechanical and manufacturing reasons, appeared to be the appropriate choice. It is able to reach a strain rate of the order of magnitude of 10^4 1/s, displacement up to 0.6 um and forces of almost a milli-Newton, more than enough to break the nano-wires. The electric connections of the electrostatic actuated device have been designed to minimize the cross-talk effect. Phenomenon that hindered the execution of certain experiments with the previous generation devices.