A major challenge in the field of Structural Health Monitoring (SHM) of safety-critical structures is how to effectively and efficiently detect fatigue damage, especially before there is macrocrack initiation. In this dissertation, a local ultrasonic technique is developed to assess pre-crack fatigue damage in structures. The novel feature of this...
We present several multiscale quantum mechanical (QM), molecular mechanical (MM), and continuum mechanical (CM) schemes to study the strength properties of carbon nanotubes (CNTs) and graphene sheets. A bridging domain method based on overlapping domain-decomposition schemes using the Lagrange multipliers field is developed to couple an atomistic domain with a...
The addition of nanoparticles into polymer materials has been observed to dramatically change the mechanical, thermal, electrical, and diffusion properties of the host polymers, promising a novel class of polymer matrix composite materials with superior properties and added functionalities that are ideal candidates in many applications, including aerospace, automobile, medical...
In this research, the optical and electrical properties of graphene-based materials are investigated. In particular, "graphene oxide", which is an individual layer of graphite oxide, and its chemically reduced form, is probed in terms of its properties, and the properties of graphene oxide and chemically modified graphene oxide are compared...
Cells are known to respond to external stimuli such as chemical, physical and mechanical cues from their microenvironments. In this work, we developed the technology to to complement the previously reported studies that deal with substrates' mechanical property by developing thin polydimethlysiloxane (PDMS) membrane microdevices using microfabrication technology. Typically, multiples...
Various methods for solving the partial contact of surfaces with regularly periodic profiles-- which might arise in analyses of asperity level contact, serrated surfaces or even curved structures--have previously been employed for elastic materials. A new approach based upon the summation of evenly spaced Flamant's solution is presented here to...
In a highly competitive market, it is becoming increasingly important to view product design as an enterprise-level profit-driven activity. Demand models have become central to enterprise-driven design approaches since they help estimating the economic impact (e.g., revenues, profits, and cost) of a product's design. The primary contribution of this dissertation...
The macroscale mechanical and physical properties of materials are inherently linked to the underlying microstructure. Traditional continuum mechanics theories have focused on approximating the heterogeneous microstructure as a continuum, which is conducive to a partial differential equation mathematical description. Although this makes large scale simulation of material much more efficient...
There is a need for cyclic robots that interact with lower limbs. Such robots will bring new programmability to exercise, rehabilitation, psychophysiology, and physiology, allowing for complete customization of the foot pedal path and dynamics. These robots are novel to the robotics research ¯eld as well, since conventional robotic designs...
The combined trends of decreasing application size and increasing requirements for energy efficiency have driven a need for improved understanding and better predictive tools for thin film lubricated systems. Research on such systems is complicated by the involvement of both larger scale phenomena such as fluid flow, material deformation, and...