Matthew R. Begley

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Simulation of the nonlinear mechanical response of materials with explicit representation of microstructural features is extremely challenging. These models typically involve a very large number of degrees of freedom, and are prone to convergence difficulties when searching for roots to nonlinear equilibrium equations. We focus on an idealized material(More)
Neural electrodes are essential tools for the study of the nervous system and related diseases. Low electrode impedance is a figure of merit for sensitive detection of neural electrical activity and numerous studies have aimed to reduce impedance. Unfortunately, most of these efforts have been tethered by a combination of poor functional coating adhesion,(More)
Stiff ceramic platelets (or bricks) that are aligned and bonded to a second ductile phase with low volume fraction (mortar) are a promising pathway to produce stiff, high-toughness composites. For certain ranges of constituent properties, including those of some synthetic analogs to nacre, one can demonstrate that the deformation is dominated by relative(More)
The mechanical behavior of thin elastic _lms deposited onto structural alloys plays a critical role in determining _lm durability[ This paper presents analysis of an impression experiment designed to evaluate some of the relevant properties of these _lms[ The modeling provides quantitative strain information which can be used to estimate the fracture(More)
—This paper identifies dynamic excitation parameters that promote decohesion of stiction-failed microcantilevers. The dynamic response of " s-shaped " adhered beams subjected to harmonic loading is described using modal analysis; this model is then used to predict the onset of debonding in the context of a critical interface energy. These theoretical(More)
The paper presents the spectral stiffness microplane model, which is a general constitu-tive model for unidirectional composite laminates, able to simulate the orthotropic stiffness , prepeak nonlinearity, failure envelopes, and, in tandem with the material characteristic length, also the post-peak softening and fracture. The framework of the microplane(More)
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