MEMS and Nanotechnology

Advances in Thin Film Indentation (MEMS and Nanotechnology)

ABSTRACT A new method to accurately and reliably extract the actual Young’s modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior even a few nanometers into a film several hundred nanometers […]

Cyclic Nanoindentation Shakedown of Muscovite and Its Elastic Modulus Measurement

ABSTRACT A series of cyclic loading nanoindentation experiments with varied maximum loads (Fmax) of 0.05 to 2.0 mN were performed on a nanostructured, layered muscovite with loading direction normal to its basal plane. A critical load (e.g., 0.5 mN) exists that leads to distinct load-displacement curves: when Fmax is greater than this load, the loading/unloading […]

Assessment of Digital Holography for 3D-Shape Measurement of Micro Deep Drawing Parts in comparison to Confocal Microscopy (MEMS and Nanotechnology)

Abstract Fast and accurate measurement of the 3D-shape of mass fabricated parts is increasingly important for a cost effective production process. For quality control of mm or sub-mm sized parts tactile measurement is unsuitable and optical methods have to be employed. This is especially the case for small parts which are manufactured in a micro […]

Full-Field Bulge Testing Using Global Digital Image Correlation (MEMS and Nanotechnology)

ABSTRACT The miniature bulge test is an acknowledged method for characterizing freestanding thin films. Nevertheless, some discrepancies in the quantitative results from such tests can be found in literature, explained in part by erroneous assumptions in the analytical description used to compute the global stress and strain from the membrane pressure and deflection. In this […]

Experimental Investigation of Deformation Mechanisms Present in Ultrafine-Grained Metals (MEMS and Nanotechnology)

ABSTRACT Ultrafine-grained (UFG) metals possess grain sizes on the order of hundreds of nanometers and display a remarkable capacity for high strength, high ductility, and enhanced superplasticity. This paper presents the preparatory steps necessary for a high-resolution experimental investigation into the deformation mechanisms active in UFG metals. A new experimental methodology is used, in which […]

Characterization of a Variation on AFIT’s Tunable MEMS Cantilever Array Metamaterial

Abstract Metamaterials are devices with embedded structures that provide the device with unique properties. Several applications for metamaterials have been proposed including electromagnetic cloaks, lenses with improved resolution over traditional lenses, and improved antennas. This research addresses an obstacle to practical metamaterial development, namely the small bandwidth of current metamaterial devices. This research characterizes the […]

MEMS for real-time infrared imaging

ABSTRACT This project investigates an innovative approach to imaging with Micro Electro-Mechanical Systems (MEMS) based devices. By using a Linnik interferometer and advanced phase unwrapping algorithms for processing data, the feasibility of generating high-resolution grayscale images in real-time was proven with an array of individually addressable MEMS micro-mirrors. Further investigations on a thermal imaging detector […]

New Insights into Enhancing Microcantilever MEMS Sensors

ABSTRACT Damping effects on different geometries were investigated by testing them in air at different pressure levels, ranging from the atmospheric pressure of 105 Pa to 10-2 Pa. The resulting responses of these geometries followed the same trend as the analytical plot for the rectangular shape structure. As the relative resonant frequency of the structure […]

A Miniature MRI-Compatible Fiber-optic Force Sensor Utilizing Fabry-Perot Interferometer (MEMS and Nanotechnology)

ABSTRACT Magnetic resonance imaging provides superior imaging capability because of unmatched soft tissue contrast and inherent three-dimensional visualization. Force sensing in robot-assisted systems is crucial for providing tactile feedback and measuring tissue interaction forces in needle-based percutaneous procedures in MRI. To address the issues imposed by electromagnetic compatibility in the high-field MRI and mechanical constraints […]

Micromechanical Structure With Stable Linear Positive And Negative Stiffness (MEMS and Nanotechnology)

Abstract We introduce a novel micromechanical structure that exhibits two regions of stable linear positive and negative stiffness. Springs, cantilevers, beams and any other geometry that display an increasing return force that is proportional to the displacement can be considered to have a "Hookean" positive spring constant, or stiffness. Less well known is the opposite […]