Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))
Online ISSN : 2185-4661
ISSN-L : 2185-4661
Volume 77, Issue 1
Displaying 1-6 of 6 articles from this issue
Paper (In Japanese)
  • Isao SAIKI, Xun ZHENG
    2021 Volume 77 Issue 1 Pages 1-11
    Published: 2021
    Released on J-STAGE: January 20, 2021
    JOURNAL FREE ACCESS

     Shear lag and transverse shear in beams have been studied separately so far. The research on shear lag has taken cross-sectional deformation into account since its early stage. On the other hand, most of the research on transverse shear has devoted itself to determine the shear correction factor and has rarely considered the cross-sectional deformation. The authors have developed a beam theory that explicitly takes into account the cross-sectional deformation of transverse shear. On the basis of this theory, this paper proposes a beam theory that can take into account the cross-sectional deformations due to shear lag and transverse shear in a unified manner. A numerical method for determining the cross-sectional parameters required for the proposed beam theory is presented and comparison of solutions of the proposed theory with finite element solutions using continuum elements confirms the validity of the proposed beam theory.

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  • Junichi HYODO, Koji ICHII
    2021 Volume 77 Issue 1 Pages 12-20
    Published: 2021
    Released on J-STAGE: February 20, 2021
    JOURNAL FREE ACCESS

     The finite element method (FEM) is commonly used to verify seismic performance in the design of various facilities, such as buildings with pile foundations and sheet pile quay walls in Japan. It is very important to conduct validation and verification of numerical analysis. Although validations of numerical analysis is usually conducted, it is very difficult to conduct verification of non-linear problem. We did verification of modeling of pile end resistance by using FLIP ROSE. We conducted the simulation of monotonic loading test and cyclic loading test of a pile. The pile penetration was represented as the enforced displacement and the enforced load at the pile head nodes. The load-settlement relationship of enforced displacement did not agree with that of enforced load when the effective confining pressure of ground elements at the pile tip goes zero. However, when the ground nodal points within the pile diameter are constrained not to occur tensile stress, the load-settlement relationship of enforced displacement agreed well with that of enforced load. Finally, we could confirm the verification of modeling of pile end resistance using FLIP ROSE.

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  • Atsuhiro MIYAGI, Hajime YAMAMOTO, Youhei AKIMOTO
    2021 Volume 77 Issue 1 Pages 21-34
    Published: 2021
    Released on J-STAGE: March 20, 2021
    JOURNAL FREE ACCESS

     For commercial scale deployment of Carbon dioxide Capture and Storage (CCS), multiple wells will be required to inject a large volume of CO2 into a deep reservoir. Multiple well placement is the key to realize required injectivity and capacity of the reservoir. Recent studies showed that an optimization tool combining metaheuristics including the generic algorithm with numerical simulators is effective for optimizing many well parameters such as injection and production rate and well locations simultaneously. However, calculation time for the optimization could be a problem because the tool requires some thousands of simulations. Especially, applying the tool for a model in a real CCS project that reflects heterogeneity of physical properties is not realistic. In this research, we proposed a new method for mitigating the problem by leveraging parallel computation technique and supercomputer. The method was applied for an optimization tool combining a parallel reservoir simulator TOUGH2-MP with a meta-heuristics Covariance Matrix Adaptation Evolution Strategy (CMA-ES). The practicality of the tool on a supercomputer Oakforest-PACS (0.55 million CPU cores) was investigated through case studies of well placement optimization in a heterogeneous reservoir model. As a result, the tool could find optimum solution within the realistic time (several weeks). The result suggests that the tool can contribute to optimize well placement in a real CCS project.

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  • Hideto NONOYAMA, Yoshihisa MIYATA, Richard J. BATHURST
    2021 Volume 77 Issue 1 Pages 35-45
    Published: 2021
    Released on J-STAGE: March 20, 2021
    JOURNAL FREE ACCESS

     With the growing interest in risk-based design, the choice of analysis method to estimate deformation, damage, and failure of geotechnical structures is important. The authors aimed to develop a SPH analysis method for analysis of reinforced soil walls. The general approach is based on the framework of the existing SPH analysis method. The fill material is represented by an elasto-plastic model considering dilatancy, the reinforcement-soil region is represented by a composite material model, and the facing panels are represented by a rigid body. In order to verify the proposed method for deformation and damage analysis, a full-scale model loading test, carried out at the Royal Military College of Canada, was simulated. The applicability of the proposed method for failure analysis is also demonstrated by investigating the scenario of a reinforced soil wall with functional loss of foundation and facing panels. The analysis results show that the the proposed method can be applied for deformation and damage analysis and that it also provide useful information for failure analysis.

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  • Yuya KANEUJI
    2021 Volume 77 Issue 1 Pages 46-61
    Published: 2021
    Released on J-STAGE: April 20, 2021
    JOURNAL FREE ACCESS

     The inflow behavior of liquid into the branching of the capillary can be related to the capillary phenomenon. To elucidate the fundamental behavior of liquid flowing into the branching of the capillary, this paper considers the contact between the vertical capillary and the horizontally moving liquid surface and defines an inflow phenomenon of liquid into the capillary. Additionally, this paper assumes that the inflow phenomenon of liquid into the capillary occurs before the capillary phenomenon and defines a time region related to each phenomenon. In each time region, a governing equation in terms of capillary rise considering these effects is derived by the balance of pressures or forces, and a mathematical solution is derived by solving a first-order ordinary differential equation. The adequacy of the proposed mathematical solution is verified by the comparison of the capillary rise dynamics between the analytical results based on the proposed mathematical solution and the experimental data.

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  • Tohya KANAHAMA, Takanori FUJIMURA, Motohiro SATO
    2021 Volume 77 Issue 1 Pages 62-71
    Published: 2021
    Released on J-STAGE: July 20, 2021
    JOURNAL FREE ACCESS

     Wild trees have solid cross sections and heavy branches. In order for trees to grow tall and large in their living environment, the ability to properly control their weight are required. The various mechanical rationalities to buckling under self-weight are hidden in trees form, it is therefore conceivable that clarification of them makes realization rational tower structure possible. The purpose of this study is to derive the theoretical solution of critical height for self-weight buckling in tapered trees and clarification the mechanical rationalities of tapered form. We model trees as cylinder with various tapers and derive theoretical solutions by effectively using boundary and mechanical conditions. By this study, theoretical solutions of critical height in tapered trees were derived and the simple calculation formulas were obtained by nonlinear regression analysis. Moreover, the theoretical and FEM based numerical solutions were compared with each other.

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