The electronics industry drives a great deal of research towards inventing methods for creating smaller devices. In order for the current trend of the diminishing size of electronic devices - such as cell phones and laptops - to continue, two main breakthroughs are necessary: firstly, the electronic components themselves must become smaller without a loss of computing power; and secondly, the batteries that store the energy for these devices must also become smaller without a loss of capacity. Semiconductor nanowires and graphene present promising solutions for making smaller electronic circuits, while lithium-ion batteries are currently the most space-efficient energy-storage device. In order for nanowires, graphene, and lithium-ion batteries to gain widespread use, both their performance and reliability are of paramount importance. Despite the fact that these nano- and micro-scale structures are not directly under mechanical loads, their reliability is still largely dictated by mechanical failure during use, and therefore must be well-understood. To this end, the work presented herein describes detailed analyses of fracture and failure in these small-scale structures. At the nanoscale, fracture in faceted semiconductor nanowires and graphene sheets containing grain boundaries has been studied using molecular dynamics techniques. Interestingly, the results of the molecular dynamics simulations of the nanowires can easily be explained using continuum fracture mechanics, while the results of the graphene sheets with grain boundaries are in complete discord with continuum theories and general intuition. In the case of the lithium-ion batteries, finite element simulations of crack propagation in electrodes have been used to understand how initial defects grow in graphite and silicon electrode particles during battery charging and use.
Grantab, Rassin,
"Computational Studies of Fracture in Micro- and Nano-Scale Structures"
(2012).
Mechanics of Solids Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0RN3659
