内容の概要説明：

Testing material properties at the nanoscale using specially designed nanostructures will be discussed in the first part of the talk. The emerging field of nanotechnology requires basic understanding of the mechanical behavior of materials at the nanoscale. Ideally, one would perform testing on suitable nanoscale  specimens that mimic the common macroscopic samples. However, both the fabrication and the actual testing of such small samples are challenging. In the present work, we measure the elastic and inelastic  behavior of individual (isolated) helical nanosprings and nanorods fabricated by the oblique angle deposition with substrate rotation  using a tip-cantilever assembly attached to a conventional atomic force microscope (AFM). The fatigue behavior of these nanostructures is also studied. Applications of nanostructures to nano- electromechanical pumps and as compliant inter-layers in microelectronic devices will be discussed.
The second part of the talk will address the mechanics of composite materials with hierarchical microstructure. Many such materials exist  in nature, including biological materials, which are typically structured on multiple scales, from the nano to the macroscale, as  well as some rock and aerogels. In such materials the amount of  geometric detail observed in the microstructure increases from scale to scale in a self-similar manner. To solve mechanics boundary  value problems on these structures using current multiscale methods is impractical since no scale decoupling can be identified. I will present a method for solving boundary value problems defined on such stochastic, self-similar structures. As an application, I will show that semiflexible random fiber networks, such as the eukaryotic cells cytoskeleton, belong to this class, will discuss the implications of  this observation on the mechanics of the network and will demonstrate how one can solve boundary value problems defined on the scale of the  entire cell.

日時：2009年7月2日(木）14:45 ~ 16:15

場所：東京大学工学部 2号館2階222講義室

添付ファイル： 第23回公開セミナー.pdf