1. ホーム
  2. 機能創成セミナー

機能創成セミナー Seminar on Mechanical Science and Bioengineering

基礎工学部棟 D404-08 共用セミナー室(D棟4階)
Multiscale and Multiphysics Analyses of Composites
Materials have their hierarchical structures from nanoscale to macroscale. The structures in each length scale influence the bulk properties of the materials. In order to understand and predict macroscale properties of materials, it is important to analyze the roles and links of different length scales. To this end, multiscale analyses have been undertaken for different materials such as composites, metals, biomaterials, etc. The multiscale analysis spans from the molecular level to the macroscale level. As an example, a generalized multiscale analysis model has been developed for various composites materials including fiber composites, particulate composites, short fiber composites, etc. Very recently, new failure criteria were proposed for fibrous composite materials. The criteria are based on distinctive failure modes of the constituent materials such as fiber fracture, fiber buckling, matrix cracking and fiber/matrix interface debonding. The criteria use the stress and strain occurring in the fiber and matrix materials. Human bone was also analyzed using a similar multiscale approach. Then, a metallic material was briefly studied.
Young W. Kwon, Distinguished Professor
Dept. of Mechanical & Aerospace Engineering, Naval Postgraduate School, USA
Multiscale modeling of the thermal fluctuations of dislocations and the coarsening of connected structures
My talk will consists in two separate parts. The first part of my talk will focus on the thermal fluctuations of dislocations. The plastic behavior of metals and alloys is mostly controlled by the displacement of linear defects called dislocations. However, the behavior of these defects in temperature remains partially known due to the complexity of the strain field generated in their vicinity. We have recently derived an analytical solution for the energy of a weakly perturbed dislocation, allowing to characterize analytically the thermal fluctuations of straight dislocations. This analytical description matches remarkably well the fluctuation spectrum obtained from large scale molecular dynamics simulations, and reveal the interplay between long-range elastic interactions and the core energy of the dislocation. The second part of my talk will focus on the coarsening of connected structures by surface diffusion. Nanoporous and microporous materials are of great interest in a number of applications ranging from battery anodes to captors and capacitors. When surface diffusion is thermally activated, these porous microstructures evolve in time, leading to a descrease of their surface area and a drop of the properties of the materials. Using a phase-field model for surface diffusion, we have investigated the coarsening behavior taking place during the evolution of these structures. More specifically, we focused on the interactions between the morphological and topological characteristics of these structure during their evolution.
Pierre-Antoine Geslin
CNRS Researcher, Mateis lab, CNRS/INSA Lyon, Villeurbanne, France
世話人:君塚 肇 / 参加者:未定
坂根 亜由子
世話人:出口真次 / 参加者:未定
豊中キャンパス 基礎工学部 G棟5階 G509
固体粒子を含む乱流は,河川における土砂の輸送や流動層反応器など, 多くの自然現象,工業プロセスと関係しており,そのダイナミックスの 理解が求められている.数値シミュレーションは,実験では入手困難な 詳細な情報を得ることが可能であることから,そのダイナミックスを解 明するための重要なツールとなっている.これまでに,コルモゴロフ長 よりも十分に小さな微小粒子に対して,質点近似を用いた多くの解析が なされてきたが,近年では,コルモゴロフ長よりも大きな有限サイズの 粒子に対して,粒子周りの流れをも完全に解析する「粒子解像シミュレー ション」が盛んに行われるようになっている.セミナーでは,粒子解像 シミュレーションを行うための幾つかの計算手法について,その問題点 などを解説するとともに,埋込境界法を用いて実施した有限サイズ粒子 を含む一様せん断乱流の数値シミュレーション結果を紹介する.
田中 満
(京都工芸繊維大学 工芸科学研究科 機械工学系)
世話人:後藤 晋 / 参加者:未定
豊中キャンパス 基礎工・国際棟セミナー室
Molecular Biomechanics and Cellular Mechanotransduction in Health and Disease
Living cells sense mechanical signals, and respond actively by changing their phenotype. This process, termed as cellular mechanotransduction, is mediated by a combination of biochemical and biophysical mechanisms via mechanically induced changes in the structure and function of specific molecules and molecular complexes. Our specific attention is on the role of three macromolecular systems in cellular mechanotransduction, namely the integrin-mediated focal adhesions bridging the cell with the extracellular matrix (ECM), and linkers of the nucleoskeleton and cytoskeleton (LINC complexes), and the nuclear pore complex (NPC) at the interface between the cytoplasm and nucleus. Focal adhesions are the immediate sites of cell interaction with the ECM, and as such they play a key role in mechanosensing and mechanotransduction at the edge of the cell. LINC complexes physically link the cytoskeleton and nucleoskeleton to regulate force transmission to the nucleus; their direct associations with focal adhesions through filamentous actin bundles results in ultrafast mechanotransduction. Nuclear pores could also play a role in the overall process of cellular mechanotransduction by exquisitely controlling the material transport in and out of the nucleus, thereby regulating gene expression and protein synthesis. In this seminar, I will present some of our recent efforts aimed at better understanding of these interconnected molecular systems in the context of cellular mechanotransduction.
Mohammad R. K. Mofrad, Professor
Departments of Bioengineering and Mechanical Engineering, University of California Berkeley
世話人:出口真次 / 参加者:未定
豊中キャンパス 基礎工学部 D棟4階 セミナー室
藤原 進(京都工芸繊維大学 材料化学系)
世話人:後藤 晋 / 参加者:未定
大阪大学基礎工学研究科 C棟4階 C419室
Inference of the stress field of a cell sheet
The mechanical behavior of living tissues is deeply connected with many important biological questions, yet little is known about internal tissue mechanics. Since the traction forces exerted by cells on a planar, deformable substrate can be measured, we propose to combine traction force data with Bayesian inversion to estimate the internal stress field of a cell sheet. The method is validated using numerical simulations performed in a wide range of conditions. It is robust to changes in each ingredient of the underlying statistical model. Importantly, its accuracy does not depend on the rheology of the tissue. Combining Bayesian inversion with Kalman filtering allows to process time-lapse movies of the traction force field. As an example of application, we provide an estimate of the tissue stress field close to cell delaminations in an epithelial cell monolayer.
Philippe Marcq (Institut Curie)
世話人:出口 真次 / 参加者:未定
豊中キャンパス 基礎工学部 D棟4階 セミナー室
前半では球状容器内部でのMHD構造形成に関する最近の我々の研究を3つ 紹介する:(1) MHD緩和(単位球内部のMHD流体の磁気・運動エネルギー 緩和と構造形成)、(2) 球殻MHD対流(正多面体の対流パターン形成とそ のダイナモ)、(3) 薄い球殻での対流(single spiralパターンの形成)。 後半では大規模シミュレーションにおける可視化で現在標準的な方法と なっているポストプロセス可視化に代わる新しい可視化手法とその開発 状況を紹介する。
陰山 聡 教授
世話人:後藤 晋 / 参加者:未定
基礎工学研究科A棟 A304講義室
Forging Mens et Manus: the MIT Experience in Upper and Lower Extremity Robotic Therapy
The field of rehabilitation robotics has grown steadily over the past decade, making significant clinical contributions. Studies have demonstrated both the efficacy and advantages of robotics for assessing and treating motor impairment. Recent guidelines, such as the 2010 AHA American Heart Association’s “Comprehensive Overview of Nursing and Interdisciplinary Rehabilitation Care of the Stroke Patient,” endorsed the use of rehabilitation robotics for upper extremity rehabilitation. The same is true of the 2010 VA/DOD guidelines. The recent 2016 AHA guidelines reaffirmed the same standing. The purpose of this talk is (1) to provide a concise yet broad-based review of the neuroscience basis of motor rehabilitation for the upper and lower extremity, (2) a historical perspective on how the field has developed, (3) review the state-of-the-art for upper extremity robotics, (4) and lower extremity rehabilitation robotics, and (5) describe on-going research at MIT.
Hermano Igo Krebs, Ph.D

IEEE Fellow
Principal Research Scientist & Lecturer
MIT, Mechanical Engineering Dept

Adjunct Professor
University of Maryland, School of Medicine, Dept Neurology

Visiting Professor
Osaka University, Mechanical Science and Bioengineering Dept
Fujita Health University, School of Medicine
Newcastle University, Institute of Neuroscience
Loughborough University, The Wolfson School of Engineering

Member Scientific PhD Board
University Campus Bio-Medico of Rome, Programme Bioengineering & Biosciences
世話人:平井 宏明 / 参加者:未定