Recently, aging of steel structures such as conveyor frames has been a big issue in steelmaking works. It may lead to fatal breakdown of production lines and increase of maintenance and renovation cost. In order to solve this problem, a new damage assessment technique based on vibration measurement has been developed. The maximum stress in a conveyor frame, which is one of the most important elements to evaluate structural integrity, can be deduced from its natural frequency of the 1st bending mode. The validity of the technique has been verified by numerical simulation and proof-of-concept experiments. It enables us to assess and maintain conveyor frames properly, and contributes to the steady delivery of the products.

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   A rust state has an important effect on the service life of weathering steel bridges. In this paper, the surface roughness of weathering steel is quantitatively evaluated by using three-dimensional photograph measurement. The effects of the illuminance in the laboratory and distance between the camera lens and the samples on the measure results are investigated. The present results are also compared with those obtained by the other methods. Furthermore, present method was applied to the existing weathering steel bridges.

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   In this paper, a sampling moirè camera is applied to a dynamic displacement measurement of a steel railway bridge while a train is passing. A sampling moirè method is one of the convenient phase analysis methods. The accuracy of phase difference analysis is from 1/100 to 1/1000 of the grating pitches. This method is useful to a real-time displacement measurement because the two-dimensional phase analysis can be performed from a single shot two-dimensional grating image. Recently, we developed a sampling moirè camera which can analyze the two-dimensional displacement images in real-time by using sampling moirè method. The camera can measure dynamic displacement of the object. The experimental result of a dynamic displacement measurement of a steel railway bridge while a train passing shows that the variation of the measurement displacement is similar to the predicted displacement behavior. The possibility to apply the sampling moirè camera for the displacement measurement of a steel railway bridge is confirmed.

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   In order to know the structural characteristics of concrete structures, cracks generated into the concrete structure are important survey items. If one can accurately predict the cracking behavior, it is possible to contribute significantly to the cracking control technology. In this study, compression tests are performed using a gypsum plaster board having a circular hole, a crack and two cracks. And then their influences for crack generation and progression have been investigated. The measurement method was used for high-speed camera and digital image correlation.

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   This study aims to investigate a Lagrangian vortex particle method for tracking a viscous fluid interface. Unlike usual Eulerian schemes such as Level-Set method, Volume-of-Fluid method and CIP method, this paper proposes a Lagrangian scheme in which the continuity equation is established by the density difference across the interface. Then, the density difference across the interface is calculated by the distribution of the source singularities on the interface, and the surface tension relates to the time evolution of the strength of the vortex particles.

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   Microscopic particles suspended in a fluid flow experience a fluctuation force caused by thermal agitation of solvent molecules such as the Brownian force. Previous works of the Stokes flow have been often solved in a linear hydrodynamic interaction system with a deterministic non-hydrodynamic force or a stochastic force such as the Brownian force and, hence, the hydrodynamic force has been linearly evaluated for the velocity of the bulk flow at the center of the particle. However, our earlier works showed that the nonlinear hydrodynamic interaction would not be so small when the particle abruptly moves with a rotation. The purpose of this study is to establish the numerical strategy to deal with the nonlinear hydrodynamic force acting on a particle and to give some results of the particle motion with the nonlinear Brownian movement.

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   In this paper, the propagation behavior of elastic waves generated in CFRP laminates by pulsed laser was investigated both experimentally and analytically. First, the anisotropy in amplitudes of elastic waves generated by pulsed laser were measured experimentally. The anisotropic property was found to vary with different frequencies. Secondly, elastic wave propagation behavior was evaluated by finite element analysis. In this analysis, two cases in which CFRP has anisotropic and isotropic thermal expansion properties were compared with experimental results. As a result, tendency in analytical results of CFRP with anisotropic thermal property agreed well with the experimental results, which confirms that the anisotropic thermal expansion property of CFRP laminates causes the anisotropy in amplitudes of elastic waves generated in CFRP laminates by pulsed laser. Finally, the influence of coatings on anisotropic behavior of elastic waves generated in CFRP laminates by pulsed laser was investigated by wave measurement test of CFRP specimens with coatings used for outer skins of aircrafts.

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   A method for estimating J-integral from optically measured displacement fields for a power-law hardening material is described in this paper. The displacement gradients and strains along the circular path of the integration are determined from the measured displacement fields using the method of least-squares. Then, the stresses are determined using the elastic-plastic constitutive relations. J-integral values are then obtained by performing the numerical integration along the path. The effectiveness is demonstrated by applying the method to the displacement fields obtained using elastic-plastic finite element analysis and digital image correlation for single edge notched specimens. Results show that the J-integral values can be obtained by the proposed procedure.

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   Speckle interferometry-digital image correlation hybrid method is proposed for wide range strain measurement. Speckle interferometry has a good measurement range for elastic deformation of metallic materials. On the other hand, digital image correlation has a good measurement range for plastic deformation of metallic materials. Strain distribution measurement ranging over elasto-plastic deformation is realized by combination of these two methods. In the proposed method, therefore, two methods are applied to same measurement field for measuring elasto-plastic deformation. Then, two data groups obtained by each method are combined. Overlapped region between two data groups is arranged and these data groups are combined by moving least-squares. As the result, continuous strain distribution of elasto-plastic deformation ranging over four orders of magnitude, from 10^-6 to 10^-2 is obtained.

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   The values of heat-transfer coefficients decrease in a drag-reducing surfactant solution flow. Therefore, it is necessary to develop an effective method for enhancing the heat transfer of a surfactant solution flow. The objective of this study is to examine the heat transfer enhancement effect when microbubbles are injected into a drag-reducing surfactant solution flow. Specifically, the relationship between microbubble size and the heat transfer enhancement of a surfactant solution flow was investigated experimentally. Microbubbles were generated using a porous metal pipe placed in a test pipe. Microbubbles having different sizes were generated by using three types of porous metal pipes. The flow patterns observed in air microbubble-surfactant solution two-phase flows were fine bubbly; these patterns were independent of microbubble size. The heat transfer enhancement effect depends on the air-surfactant solution flow ratio or microbubble size. An increase in the air-surfactant solution flow ratio or decrease in the microbubble size leads to a greater heat transfer enhancement effect.

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