AMN SEMINAR SERIES: Challenge for Fracture Nanomechanics
Challenge for Fracture Nanomechanics
As materials with nanoscale dimensions are used in various applications such as semiconductors, sensors, and nano-electromechanical-systems, the investigationson their mechanical behavior have been attracting many engineers/researchers until now. Moreover, the knowledges on mechanics/mechanism of materials behavior in nanometer scale contributes essential understanding on the strength of macro-components as well. In general, mechanics in nanoscale materials is significantly different from that in macro-scale counterpart. For example, internal nano structures such as dislocations, grain boundaries, and various defects directly govern the mechanical properties of such materials. In addition, the mechanical behavior of nano-components is highly influenced by the surfaces. This points out that the fracture characteristics with nanoscale geometric factors provide fundamental wisdom on the strength of materials. Then, it is important to develop a new concept of fracture mechanics in nanometer scale, namely “Fracture Nanomechanics” (1). However, the experiments in these scales are extremely challenging in fabrication, handling, and inspection of the specimen and the measurements of load and displacement during the test. Moreover, we have to understand the fracture phenomenon from atomic behavior in principle. We need proper combination of analytical methods such as finite element method (continuum mechanics), molecular dynamic simulation (atomic mechanics) and ab initioone (quantum mechanics) with the experimental results obtained on the basis of sophisticated methodology for the investigations. In this lecture, I introduce my team’s challenges of the experimental and analytical studies on fracture nanomechanics (reaching single digit nanometer range). I hope that the understandings of nanoscale fracture can provide critical insights for the reliability of nanoscale devices as well as macroscale components.
(1) Kitamura T., Sumigawa, T., Hirakata, T. and Shimada, T., 2016, Fracture Nanomechanics, 2nd Edition, CRC Press.