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  • Accurate, High-Speed, Full-Color and Vibration-Resistant 3D Shape Measurement Using Linear LED Devices
  • Abstract Several types of accurate and high-speed 3D shape measurement using linear LED devices were developed by author's research group. The linear LED device is a key device to develop them. High-speed phase shift synchronized with camera triggers can be achieved by switching the lighting position of the linear LED. The control signals can be generated easily with a no special micro-computer. A compact projector unit can be produced. Author also proposed a calibration method, named a whole-space tabulation method (WSTM), for an accurate and high-speed shape measurement using multiple reference planes. A handy, fullcolor and real-time 3D shape measurement unit…
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  • Fully Phase-Wise Conservative and Bound-Preserving Algorithms for Multiphase Flow in Geological Formation
  • Abstract Modeling and simulation of multiphase flow in porous media have been a major effort in reservoir engineering and in environmental study. Petroleum engineers use reservoir simulation models to manage existing petroleum fields and to develop new oil and gas reservoirs, while environmental scientists use subsurface flow and transport models to investigate and compare for example various schemes to inject and store CO2 in subsurface geological formations, such as depleted reservoirs and deep saline aquifers. One well cited requirement is to conserve the mass globally and locally, but most popular methods of N-phase flow used in practice conserve mass only for…
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  • Phase analysis for out-of-plane displacement measurement using laser lines generated in camera with diffraction grating
  • Abstract In this study, a sampling moire method in which parallel laser lines were generated in a camera using a diffraction grating was proposed. A green laser of line projection function, a diffraction grating and an industrial camera were used as an experimental device. Object images with laser line projection before and after displacement were taken by the camera. Displacements that calculated by a sampling moire method and a method of averaging center-ofgravity were be compared. Results show that the proposed method is more precision than method of averaging center-of-gravity.
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  • A Method for Measuring Displacement and Strain of Rubber Sheets with Large Deformation Using Digital Image Correlation
  • Abstract This study establishes a method to measure the displacement and strain of rubber with large and fast deformations using digital image correlation. In order to elucidate the mechanism of growth of a crack and to investigate the complex behavior of a crack tip, which is important for that purpose, displacement and strain near the crack where large strains are locally generated by stress concentration are measured. A displacement restraint rubber sheet of a strip fixed at upper and lower ends with an initial crack is used as a test piece. A constant rate displacement load is applied to it, its…
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  • Inverse Analysis of Viscoelastic Material Properties Considering Time- and Temperature-Dependence of Poisson’s Ratio
  • Abstract This study proposes a method for identifying viscoelastic properties that considers time- and temperature dependence of Poisson's ratio using inverse analysis. In this method, displacement distribution, which are input values of inverse analysis, is measured by digital image correlation [1], and unknown material properties are determined using the virtual fields method [2]. This method targets plane stress condition and the Poisson's ratio of the viscoelastic body depends on the time and temperature [3]. This study focuses on the correspondence law and proposes a method for calculating stresses considering time- and temperature dependence of Poisson's ratio. In-plane strains are measured and…
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  • Multi-physics CFD Simulation in a Jet Engine
  • Abstract In a turbine of a jet engine, deposition phenomenon is often observed. Deposition is a phenomenon that particles such as volcanic ash, sand and dust passing through a combustion chamber of a jet engine are melt, rapidly cooled and then accumulate on the turbine blade and end-wall surfaces. Deposition is one of critical problems when aircraft flies in a cloud with many particles. Obviously, deposition can degrade the aerodynamic performance of the turbine blade and vane, and make partial or complete blockage of film-cooling holes. As the result, deposition deteriorates safety and life time of the turbine. In the past…
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  • Symmetric Notches Cause Strengthening in Brittle Metallic glasses
  • Abstract For all engineering materials, the flaws are introduced inevitably from fabrication, mechanical damage, and corrosion. These stress raisers always induce catastrophic failures and it is therefore of great importance to understand the effect of flaws on the mechanical properties of engineering materials. The effect of flaws on metallic glasses (MGs) is a debatable topic because many relevant works have reported notch strengthening, notch weakening and notch insensitivity for brittle MGs. The significant notch strengthening of MGs was attributed to the transition of failure mechanism, from catastrophic shear banding to ductile fracture. Here we investigate systematically the influence of notch geometry…
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  • Residual Strength and Microdamage of Cortical Bone After Non-Destructive Creep Loading
  • Abstract Bone tissue is a viscoelastic material which shows time-dependent mechanical manner. Moreover, it is known that bone microdamage is generated by physiological normal mechanical loading in vivo [1-3]. In order to know basic insight into the adverse effects of creep loading on bone strength, in the present study, we focused on the mechanical behavior of cortical bone after nondestructive creep loading at high stress magnitude. Cylindrical specimens were obtained from cortical bone in the longitudinal and tangential direction of bovine femur. We statically applied a compressive stress to the specimens (creep group) for 24 hours. The specimens without creep loading…
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  • Estimation of Turbulent Flow from Wall Information via Machine Learning
  • Abstract Along with rapid development of computer technologies, a wide range of turbulent flows have been investigated by direct numerical simulations and the big databases have been built throughout the world. From the DNS results, we can investigate turbulent characteristics in three-dimensional space and time. In the laboratory experiment, we can apply sophisticated laser diagnostics technique to measure flow field non-invasively in research. On actual equipment, it is very difficult to get the flow field data away from the wall. We can measure only wall information, such as wall shear stresses and pressure. When we predict turbulence from wall information, we…
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  • Nonlinear Vibration Analysis of Seismic-isolation Laminated Rubber Considering Bi-directional Restoring Force Model
  • Abstract The seismic-isolation laminated rubber is used as a means of suppressing damage to the structures caused by an earthquake. To design the seismically isolated structure, it is important to calculate the dynamic response reflecting the rubbers characteristics accurately. The authors have applied the nonlinear vibration analysis method using the restoring force model of the power function type to the seismic response analysis of seismic isolation rubber in horizontal unidirectional [1-3]. However, when seismic isolation laminated rubber is loaded in horizontal bi-direction, the seismic isolation laminated rubber is torsional deformed and breaks with less force than when loaded in unidirectional. It…
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