A5088679237- Numerical methods in engineering
- Structural Health Monitoring Techniques
- Indoor and Outdoor Localization Technologies
- Fluid Dynamics Simulations and Interactions
- Energy Efficient Wireless Sensor Networks
- Optical measurement and interference techniques
- Ultrasonics and Acoustic Wave Propagation
- Landslides and related hazards
- Structural Response to Dynamic Loads
- Mechanical Behavior of Composites
- Geotechnical Engineering and Underground Structures
- High-Velocity Impact and Material Behavior
- Rock Mechanics and Modeling
- Structural Behavior of Reinforced Concrete
- Underwater Vehicles and Communication Systems
- Geological Modeling and Analysis
- Soil and Unsaturated Flow
- earthquake and tectonic studies
- Geophysics and Gravity Measurements
- Evacuation and Crowd Dynamics
- Dam Engineering and Safety
- Thermography and Photoacoustic Techniques
- GNSS positioning and interference
- Seismic Performance and Analysis
- Non-Destructive Testing Techniques
Japan Agency for Marine-Earth Science and Technology
2020-2024
Keio University
2008-2019
The University of Tokyo
1997-2009
Earthquake Engineering Research Institute
2003-2009
Tokyo University of Science
2008
California Institute of Technology
1999-2001
Takenaka (Japan)
1988
Toshiba (Japan)
1982
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
Abstract This paper presents the particle discretization scheme (PDS) to analyze brittle failure of solids. The uses characteristic functions Voronoi and Delaunay tessellations discretize a function its derivatives, respectively. A discretized has numerous discontinuities so that these are utilized as candidate crack path segment in modeling propagating cracks, without making any extra computation accommodate new displacement discontinuities. When is implemented finite element method (FEM),...
Results from an experimental investigation on the mechanical behavior of a unidirectional fiber reinforced composite with 50% volume fraction E-glass/vinylester and vinylester matrix under uniaxial proportional multiaxial compression are presented. The stress-strain curve acoustic emission records together post-mortem observations specimen show failure mode transition axial splitting to kink band formation as loading condition changes compression. Axial "splitting induced" were observed in...
Results from an experimental investigation on the mechanical behavior of a unidirectional fiber reinforced composite with 50% volume fraction E-glass/vinylester and vinylester matrix under uniaxial proportional multiaxial compression are presented. The stress-strain curve acoustic emission records together post-mortem observations specimen show failure mode transition axial splitting to kink band formation as loading condition changes compression. Axial "splitting induced" were observed in...
We study the effects of structural inhomogeneity on quasi-static growth strike-slip faults. A layered medium is considered, made up an upper layer bounded by a free surface and welded to lower half-space with different elastic property. Mode III crack employed as mathematical model fault, which nucleated in then propagates towards interface. adopt FEM-β, newly proposed analysis method for failure, simulate quasi-statistic governed stress distribution media. Our results show that along planar...
Some experimental observations of Shock Wave Lithotripsy(SWL), which include 3D dynamic crack propagation, are simulated with the aim reproducing fragmentation kidney stones SWL. Extracorporeal shock wave lithotripsy (ESWL) is by focusing an ultrasonic pressure pulse onto stones. models fine discretization used to accurately capture high amplitude shear waves. For solving resulting large scale propagation problem, PDS-FEM used; it provides numerically efficient failure treatments. With a...
Residual stress field is a self-equilibrium state of in the bulk solid material with inhomogeneous inelastic deformations. The high level tensile residual often leads to dynamic fracture resulting instantaneous and catastrophic destruction materials because cracks are fed strain energy initially stored due stress. dissipation crack growth results release redistribution In this paper, we propose an effective mathematical model numerical analysis method for field. We formulate behavior...
Residual stress has been empirically utilized for industrial applications to control material strength and shape of fragments. The interaction between the dynamically growing cracks residual field is sufficiently complicated prevent us from building effective models. To rigorously evaluate release redistribution in dynamic fracture process, we develop a mathematical model numerical analysis method field. Our methodology simple rigorous applicable regardless materials scales.
Abstract This study presents numerical analyses for edge chipping by impact loading. As a analysis method, we extend Particle Discretization Scheme Finite Element Method (PDS-FEM) developed the authors to be able simulate fracture due We performed simulations targeting of soda-lime glass rigid steel sphere and examined crack morphology while varying diameter impactor, velocity, distance. The proposed method successfully simulates 3D complex pattern on such as Hertzian cone conchoidal chip...
本論文は,地震時避難行動予測のために開発された,多様な群集が雑然と避難する状況を想定したエージェントシミュレーションを説明する.エージェントは見る,考える,動くことができ,固有の移動速度で避難経路モデル内を自律的に移動する.移動速度は混雑時や緊急時の人々を写したビデオ画像を解析することで求めており,避難経路モデルはGISやCAD図面から自動構築される.狭隘な街路,地下鉄駅,大型地下空間を対象に,開発したシミュレーションを実行した.さまざまな想定での群集避難の危険性を分析するとともに,密集空間の危険性の相対比較を試みた.
Unidirectional fiber-reinforced composites are often observed to fail in a longitudinal splitting mode the fiber direction under far-field compressive loading with weak lateral confinement. An energy-based model is developed based on principle of minimum potential energy and evaluation effective properties obtain an analytical approximation critical stress for splitting. The analytic estimate strength used illustrate its dependence material properties, surface energy, volume fraction,...
破壊現象の簡便な数値解析手法, FEM-βを提案する. FEM-βは, いたるところ不連続かつ重なりのない形状関数と, 双対図形によるひずみ場・応力場の離散化を用いて, 連続体の数理モデルである境界値問題を数値的に解く手法であり, 特殊な変位場を用いた有限要素法 (FEM) と位置づけられる.FEM-βは通常のFEM (一様ひずみ三角形要素) と同等の精度・局所性 (疎行列) を保ちつつ, 破壊を簡便に表現する仕組みをもつパーティクル・フィジックス・モデルを与える. この意味で, FEM-βをFEMの観点から個別要素法 (DEM) を定式化しなおしたものとみなし, 連続体との等価性を保証する相互作用バネ定数を一意に決定する仕組みを持つDEMと位置づけることもできる.