Journal of applied mechanics
Online ISSN : 1884-832X
Print ISSN : 1345-9139
ISSN-L : 1345-9139
Volume 5
Showing 1-50 articles out of 103 articles from the selected issue
  • Hiroshi Kiikuni, Hideyuki Utsumi, Ichiro Adachi, Shinsaku Tada
    2002 Volume 5 Pages 3-10
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    Water vapor relative pressure difference in construction joints of hardened cement pastes with different ages and mix proportions were evaluated analytically based on chemical potential concept. Chemical potential was formulated by a system of the cement-water lattice model, developed on the statistical thermodynamics and a general idea of mixing. A system of solution enables prediction of the relative water vapor pressure under various conditions of engineering parameter. Numerical results showed a possibility of reversal moisture transfer between jointed cement pastes depending on their respective ages and mix proportions.
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  • Hideyuki Utsumi, Hiroshi Kiikuni, Shinsaku Tada
    2002 Volume 5 Pages 11-18
    Published: August 28, 2002
    Released: March 17, 2010
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    The rate constantw as formulatedb ased on thet heoryo f ratep rocessest o showt he theoretical relationshipb etweenr eactionk ineticsa nd reactionm echanicso f cement-waters ystem. The reactionm echanicsw as formulatedb y a system of the cement-watelra tticem odel, which includest he engineeringp arameters ucha s waterc ement ratio, d egreeo f hydrationa ndw ater content.T hem ethodo f solutionw as basedo n statisticatlh ermodynamicasn da generali dea of mixing.T he methodo f this studyw as able to calculatet he ratec onstantu nderv ariousc ement properties, mix proportion and degree of hydration. Numerical examples of Gibbs' free energy and r ate constantw ere shown duringh ydrationp rocessu ndervariousw ater cement ratio, and the characteristicosf the rate constantw ere examinedu nder differentb ond water ratio.
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  • Atsushi SHIMABUKURO, Ken-ichi HASHIMOTO, Yoichi SUZUKI, Chikayoshi YAT ...
    2002 Volume 5 Pages 19-26
    Published: August 28, 2002
    Released: March 17, 2010
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    Subject to an inclinedl oad, w e obtaint he energyr eleaser ate for a crackw ith an interfaceb oundedb y two different isotropic elastic materials. The energy release rate is calculated by the path independent E-integral using the finite element method with a singular element. In the finite element analysis, we impose avoiding the contact of the extended crack which happens in the large angle kinking. Under the maximume nergyr eleaser ate criterionw, e examineth e extensionb ehavioro f interfacec rack.
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  • Ichiro ARIO, Ronny, Takanori SAGA, Katsutoshi WATANABE
    2002 Volume 5 Pages 27-34
    Published: August 28, 2002
    Released: March 17, 2010
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    Dynamic bifurcation analysis for the nonlinear oscillation on a simple aeroelastic structure is presented. This structure is the cantilever beam on the flow and it has a nonlinear system without potential energy system. It shows as complex behavior on the flutter problem caused by a parameter of controlled velocity. We observe the flutter behavior through the experiment of the flow, and try to compute the its motion on the simple model based on the discrete dynamic concept. We can readily find the focusing solution on the simple system, which is possible to obtain the map of the complex solutions on the flutter.
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  • Atsushi SUTOH, Takashi MIKAMI, Masayuki OKADA, Shunji KADOYA
    2002 Volume 5 Pages 37-44
    Published: August 28, 2002
    Released: March 17, 2010
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    In this study consists of the following two topics, one is a basic consideration on the temperatures which have shown in nonhomogeneously distributed spatial process, and the other is estimated and/or interpolation for design temperatures using Semi-Variogram which was a stochastic procedure. In the former study, temperatures can be defined from homogeneous spatial processes by means of a linear transformation. In the latter one, temperatures was interpolated by Semi-Variogram, and compared with observation data. Finally, numerical examples are worked out to demonstrate the usefulness of this metohd for a heat insulator design in planning tunnel.
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  • Atsushi SUTOH, Tadamitsu YOSHIO, Takashi MIKAMI
    2002 Volume 5 Pages 45-52
    Published: August 28, 2002
    Released: March 17, 2010
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    In this study consists of the following two topics, one is a basic consideration on data mining algorithm which is a powerful data-processingp rocedure, a nd the other is introducea nd/ord iscusst o a data miningp rocedureu singn euraln etwork.T he notion of data miningi s classifieda nd interpretedto a non-structurailn versep roblem.D ata mining meanst o discovero bjectivelyk nowledge hidden in vast amount of data. It is found that the usefulness of this data mining procedure using neural network, for finding the cause of tunnel lining.
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  • Satoshi Murakami, Kazuya Yasuhara, Hideo Komine, Tomohiro Hayano, Yuic ...
    2002 Volume 5 Pages 53-60
    Published: August 28, 2002
    Released: March 17, 2010
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    Northern Kanto Plane has severely been affected by land subsidence due to groundwater abstraction. It is necessary for decision making of abstraction to determine a precisely distributiono f groundwaterf luctuationd ue to groundwatera bstractioni n the objectivea rea. Finitee lementm ethod is used to determineh ow the groundwaterf luctuationd istributeso ver the area. It is necessaryf or calculatingin advance to know transmissivitieosf ground in the hole area.H owever, i t is difficultt o get the informationfr om in-situi nvestigationisn the case of the wide area such as the Northern Kanto Plane. In this study, therefore, the transmissivities were identified by means of back analysis of the groundwater level and abstraction data collectedf or 10 years. GIS has been used for establishingd atabasesw hich are necessaryt operformb ack analysisa nd thent o visualizet her esultsf romt he finitee lementa nalysis.
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  • Kenji OGUNI, Lalith WIJERATHNE, Muneo HORI
    2002 Volume 5 Pages 61-66
    Published: August 28, 2002
    Released: March 17, 2010
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    A new method for non-destructive measurement of arbitrary 3D stress state using photoelasticity has been developed. The new approach proposed here, namely, load incremental approach, is an attempt to solve the nonlinear inverse problem of 3D photoelasticity by the linearization of the governing equation based on high resolution in load increment. As long as the applied load increment is small enough, this method works and can reconstruct arbitrary 3D stress state.
    Results from numerical simulations show the effect of i) the number of the observations, ii) the independency of the observation directions, and iii) the material sensitivity on the performance of the proposed method.
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  • Kazuyuki NAKAHATA, Masahiro ONISHI, Michihiro KITAHARA
    2002 Volume 5 Pages 67-74
    Published: August 28, 2002
    Released: March 17, 2010
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    The principal operation of linearized inverse scattering method for the shape reconstruction of defects is the integration of the scattering amplitude in the K-space, which consists of the wave number and observation angle. In this study, the two dimensional fast Fourier transform is introduced into the inversion algorithm to evaluate the integration in the
    K-space. In the process of the 2-DD FFT, the scattering amplitude is rearranged in the K-space to take account of the Nyquist wave number. Here, the backscattered waveforms measured with the contacttype of piezo-electric transducer are fed into the fast inverse technique. It is shown that the computational time of the inversion is improved without loss of the image resolution.
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  • Kazushi KIMOTO, Sohichi HIROSE
    2002 Volume 5 Pages 75-80
    Published: August 28, 2002
    Released: March 17, 2010
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    Linearized inverse scattering method is extended for shape reconstruction of scattering obstacles in a two layered medium. In order to reduce the problem to a shape reconstruction in an unbounded medium, the present method employs an integral equation with Green's function for the joined halfspaces as a starting point. The equation is then liearized by Born and Kirhhoff approximations. Replacing the Green's function by its asymptotic expansion, the inversion fomula corresponding to the two linearizing approximatioins can be derived. As a numerical example, images of shperical and ellipsoidal rigid scatterers are reconstructed using a simulated scattered wave data. Inversion results show that both Born and Kirhhoff inversion can distinguish sphere from ellipsoide though only a part of scatterers can be reconstructed due to an aperture limitation.
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  • Yae KONDO, Tomisaku MIZUSAWA
    2002 Volume 5 Pages 83-91
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents the impact response of simply supported rectangular Mindlin plates subjected to colliding of a steel ball by using the eigenfunction expansion method and the Hertz's law of contact. The effects of impact force, contact time and material properties on the mechanism of impact response generation and the characteristics of propagation of flexural waves have been investigated. It is seen that the initial impact response of steel plates and wooden plates subjected to colliding of a steel ball shows some different mechanism on the wave propagation. Beside the difference of mechanism of impact response generation, the sound pressure calculated by the present method on the assumption of plane wave shows good agreement of the acoustically experimental result.
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  • Ling HUANG, Hiroshi HIKOSAKA, Keizo KOMINE
    2002 Volume 5 Pages 93-100
    Published: August 28, 2002
    Released: March 17, 2010
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    Prestressed concrete box girder with corrugated steel web is one of the promising concrete-steel hybrid structures applied to highway bridges. Prestress is efficiently induced into the top and bottom concrete flanges due to the so-called “accordion effect” of corrugated web. In this paper a simple 2-D analysis is presented to account for 3-D phenomena of the accordion effect using 2-D link-type elements. In the vertical direction, links are given a very high stiffness to fully transmit vertical shear force. In the horizontal direction, the link stiffness is given a value calculated from the out-of-plane bending of a folded plate forming each trapezoidal corrugation. Viability of the approach is demonstrated through comparison of experimental and numerical results on a large scale specimen of prestressed concrete beam with corrugated steel web.
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  • Kazuhisa ABE, Daisuke KATO, Kazuhiro KORO
    2002 Volume 5 Pages 101-109
    Published: August 28, 2002
    Released: March 17, 2010
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    Application of the wavelet-weighted Gaussian quadrature formula to the singular and nearly singular integrals is attempted in the context of implementation of the wavelet BEM. To achieve this, the singular or nearly singular integrand is decomposed into a singular or nearly singular but simple term and a regular part. The former is integrated analytically and the integral of the latter is calculated by the wavelet-weighted quadrature method. Moreover, in order to avoid the calculation of the Jacobian, the bases such as wavelets are described with respect to the arc length of each subboundary, and then the simplification of analytical integrals is attained. Numerical examples are presented to validate the developed method. It is concluded that the proposed method can shorten the computation time for matrix coefficients by a factor of 3 irrespective of the degrees of freedom.
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  • Yaochang HE, Toshiyuki OSHIMA
    2002 Volume 5 Pages 111-120
    Published: August 28, 2002
    Released: August 04, 2010
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    In this paper, the analysis of transient thermal bending is carried out by the three-dimensional theory of elasticity in cylindrical coordinates. Boundary conditions are simply supported along the edges and free at the top and the bottom faces of the circular plate. Loading conditions are partially sectorial thermoload of axially asymmetric distribution for z axis over the top face of the circular plate. The analysis is separated into a temperature field and a stress field. The temperature field is assumed to be a transient state and is rigorously deduced by a three-dimensional theory of heat transfer. Additional solutions are used to deal with initial terms in Fourier series which are required to satisfy the boundary conditions.
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  • Kazuhiro TANIWAKI, Sadaji OHKUBO, Hiroshi MATSUTOMO, Yoshihiko KAZEKAW ...
    2002 Volume 5 Pages 121-131
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents a unified and efficient optimum design method for nonlinear truss structures dealing with configuration and sizing variables. The necessary conditions for analysis problem are derived from the total complementary energy minimization problem and those are approximated with respect to configuration design variables. In the optimization process, the structural behaviors in addition to configuration and sizing variables are improved while satisfying both the primary design constraints and the approximated necessary conditions by using the gradient projection method without calculation of behavior sensitivities. The rigorousness, efficiency and reliability of the proposed method are demonstrated in the numerical examples.
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  • Satoru USHIJIMA, Masaki TAKEMURA, Iehisa NEZU
    2002 Volume 5 Pages 133-140
    Published: August 28, 2002
    Released: August 04, 2010
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    An implicit numerical algorithm (C-ISMAC method), which is based on an implicit-SMAC method in the staggered grid, has been proposed for incompressible flows with the collocated grid system. It has been shown that a CBP (Cell-Boundary Pressure) scheme, which utilizes Pn on cell boundaries in the prediction stage of the MAC method, is effective to deal with the pressure field. Taking account of this result, some distinctive treatments for the pressure ariable were employed in developing the C-ISMAC method. As a result of the computations, it was shown that the C-ISMAC method enables us to use higher-order schemes for spatial discretization as well as to decrease the necessary computational time.
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  • Yoshihiro UCHIYAMA, Toshitaka YAMAO, Kaname IWATSUBO, Itio HIRAI
    2002 Volume 5 Pages 141-150
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents an application of the similar mesh generation method that divides a given system into the subparts with the similar stiffness matrix in the FEM analysis of tapered beam structures subjected to lateral load. A favorable characteristic of this method is its ability to perform an efficient static condensation of the similar stiffness matrix in the FEM analysis. Several problems including material non-linearity are solved, which demonstrates the validity of the proposed method. These results are compared with those obtained using the finite element package program MARC
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  • M. Huang, T. Sakiyama, H. Matsuda, C. Morita, S.Q. Ma
    2002 Volume 5 Pages 151-160
    Published: August 28, 2002
    Released: March 17, 2010
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  • Takahiro YAMADA
    2002 Volume 5 Pages 161-166
    Published: August 28, 2002
    Released: March 17, 2010
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  • Shigeri KANKE, Isao SAIKI, Akinori NAKAJIMA, Kenjiro TERADA, Kiyohiro ...
    2002 Volume 5 Pages 167-173
    Published: August 28, 2002
    Released: March 17, 2010
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    There exists a variety of phenomenological nonlinear constitutive models such as classical flow theory in plasticity. On the other hand, the recent developments of computer and molecular dynamics enable us to analyze the mechanical behavior by atomic level microstructure and eventually to evaluate macroscale material properties. Thus, we develop multi-scale modeling that characterizes macro-scale nonlinear material properties by microscopic particle system governed by potential function. Further, we examine the relationship between nonlinear material response and pattern formation.
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  • Kazumi MATSUI, Kenjiro TERADA, Masayosh AKIYAMA, Takashi KUBOKI, Keiic ...
    2002 Volume 5 Pages 175-183
    Published: August 28, 2002
    Released: March 17, 2010
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    The influences of microstructures on the yielding and strain hardening characteristics of carbon steel are examined in the framework of computational homogenization. We first conduct the tensile tests on two kinds of specimens; steel with pearlite and spheroidized cementite structures. Then the numerical two-scale analysis is performed to simulate the tensile tests by the global-local analysis method. Using the numerical results, we clarify the micro-scale mechanisms, which characterize the macroscopic plastic behavior. Finally, the multi-scale inverse analysis method is proposed to show that the experimental facts entail the higher yield stress of ferrite (Fe) for pearlite structures.
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  • Takashi Mikami, Takanori Asai, Shunji Kanie
    2002 Volume 5 Pages 185-190
    Published: August 28, 2002
    Released: March 17, 2010
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    The phenomena of melting and solidification have many current engineering applications. For example, ground freezing problems are considered as moving boundary problems (MBP) defined in semi-infinite region. This paper presents a simple and effective numerical method for the one-dimensional MBP. By use of coordinate transformation, the semi-infinite region (0, ∞) is mapped into a finite region lying between (0, 1). To this end, we consider two mappings (an exponential map and an algebraic map). The collocation method is employed to replace a partial differential equations by a system of ordinary differential equations in time, and the resulting equations are solved by the mid-interval Crank-Nicolson algorithm. Several numerical examples are analyzed in order to show the performance of the proposed methodology.
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  • Jian-Hong WU, Yuzo OHNISHI, Hiroyasu OHTSU, Satoshi NISHIYAMA
    2002 Volume 5 Pages 191-198
    Published: August 28, 2002
    Released: March 17, 2010
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    The separation of rigid body rotation term, r0, from the other displacement variables is a breakthrough idea in original discontinuous deformation analysis (DDA) formula. Although the original linear displacement function is a fast and efficient method in computation, it loses accuracy when blocks undergo large rigid body rotations. It can be a significant problem especially when solving the problem with high speed rigid body rotation, such as rock fall problem, or the larger time interval is introduced to the problem with rigid body rotation to obtain the results within less computation steps. Up to date, it is only known that the large rigid body rotation can cause free expansion and change the weight of block in the analysis. However, the authors consider that the problem can also affect the contact judgments in open-close iterations and cause wrong contact forces in the computation. In this paper, this problem will be discussed, and a new method named “post contact adjustment” is developed and applied to the contact computation terms of DDA. After the improvements, the simulation results show better contact computations and block area preservations even when the large rigid body rotation is carried out.
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  • Hitoshi YOSHIKAWA, Naoshi NISHIMURA, Shoichi KOBAYASHI
    2002 Volume 5 Pages 199-206
    Published: August 28, 2002
    Released: March 17, 2010
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    Analyses of various real world problems related to elastic wave propagation reduce to large scale problems of three dimensional elastodynamic BIEM (boundary integral equation method) in time domain. Conventional approaches in BIEM, however, are quite expensive in large scale problems in terms of both memory requirements and the CPU time. We therefore propose improved algorithms for 3 dimensional elastodynamic BIEM in time domain and parallelize the code using MPI in order to reduce the memory requirements and the CPU time. The efficiency of the improved code is demonstrated with simple crack problems, as well as with more realistic wave analysis related to crack determination.
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  • Eiji IWASAKI, Junichi MATSUNO, Masatsugu NAGAI
    2002 Volume 5 Pages 207-216
    Published: August 28, 2002
    Released: March 17, 2010
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    In the nonlinear structural analysis, several indefinite and non-physical parameters are required to solve nonlinear simulaneous equations. It is no clear how to set those parameters. In this reason easy and distinct method are needed. In this study the minimum residual quantities method which is hased on the arc-length controlling method is proposed_ Automatic arc-length setting method, which can be automatically determined with reference to change of curvature of load-displacements curve, is proposed.
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  • Mitsuteru ASAI, Kenjiro TERADA
    2002 Volume 5 Pages 217-226
    Published: August 28, 2002
    Released: March 17, 2010
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    We propose a method for evaluating the macroscopic strength and toughness of heterogeneous brittle materials by numerical analyses of microstructures. The method is based on the mathematical homogenization in conjunction with the theoretical framework of material instability. The hybrid variational formulation, which allows us to approximate the displacement in each finite element independently, is adopted for discontinuous deformation of microstructures. Then, the overall collapse of microstructure informs us of the orientation of discontinuous surfaces. The performance of the method is well demonstrated by representative numerical examples.
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  • Kazumi MATSUI, Kenjiro TERADA
    2002 Volume 5 Pages 227-234
    Published: August 28, 2002
    Released: March 17, 2010
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    A method of multi-scale computations is developed for analyzing the quasi-static mechanical behavior of elastoplastic heterogeneous media with interfacial debonding. After posing the two-scale boundary value problem, we developed the numerical algorithm for microscopic self-equlibrated problem involving discontinuous deformations. This algorithm, which accommodates the kinematical constraints on the interfaces by the penalty method, enables us to analyze the elastic-plastic behavior with debonding without any numerical instability. The representative numerical examples well illustrate the remarkable influence of microstructures with debonding interfaces on the macroscopic elastic-plastic material behavior; in particular the macroscopic yield stress.
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  • Junichi MATSUMOTO, Tsuyoshi UMETSU, Mutsuto KAWAHARA
    2002 Volume 5 Pages 235-242
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents a computational simulation method for river problem. For the actual flow problem, it is needed to compute flow velocity, water elevation and water region at the same time. For the basic equation, unsteady shallow water equations are used. As the numerical approach, implicit FEM is proposed by bubble function. To control numerical stability and accuracy, stabilized bubble function method is used to solve finite element equations. A numerical test are shown to inspect of this method.
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  • Tetsuji IDA, Kazuo KASHIYAMA, Toshiaki ISHIKAWA, Tomoyuki UO
    2002 Volume 5 Pages 243-252
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents a multi-scale finite element method for the analysis of pavement structure based on homogenization method and layered Mindlin element. The homogenization method is employed to consider the effect of mechanical behaviors of microscopic structures of pavement. The composite plate theory is also introduced to obtain a homogenized elastic tensor. The present method is applied to two numerical examples; 2-layer plate analysis and FWD (falling weight deflector) test analysis, and the computed results are compared with theoretical, experimental and 3-D computational results. The method is shown to be a useful method for the large-scale analysis of pavement structures.
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  • Kazuya NOJIMA, Mutsuto KAWHARA
    2002 Volume 5 Pages 253-262
    Published: August 28, 2002
    Released: March 17, 2010
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    This paper presents a mesh generation technique for underground tunnels based on the 3-D Delaunay triangulation. It is a rather difficult task to make the mesh generation of tunnels because it is not easy to obtain the shape of the edge at a point where some tunnels cross each other. Thus the method which can obtain the models without calculating the edge is required. In this paper, such a method is presented. This is suggested by shield tunneling method which is used in civil engineering field. In this method, the Boolean operation is performed by using the tunneling shield module This method depends on 3-D Delaunay triangulation. The 3-D Delaunay triangulation is useful to divide a domain because it can make the tetrahedra only using the nodes which are distributed arbitrarily. This modeling process consists of two parts. The first is nodal distribution part. The second is Delaunay triangulation part. This paper gives some applications of this method to the complicated tunnel models.
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  • Katsuyuki SUZUKI, Akihiro KAMINAGA, Daiji FUJII, Hideomi OHTSUBO, Yosh ...
    2002 Volume 5 Pages 263-269
    Published: August 28, 2002
    Released: March 17, 2010
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    The multilevel finite cover method is applied to adaptive analysis of seepage flow problem. For the index of adaptivity, 2 methods are proposed, one is based on the a posteriori error estimation, and the other is the a priori estimation based on the geometric configuration. The latter method is applied to the seepage flow problem of rock including complicated cracks. The evaluation method of equivalent permeation constant is calculated based on 2 methods, one is based on the volume fraction of crack, and the other is based on the integration along the crack. The latter one is more accurate, but for large scale problem former one is less memory consuming. The rock model with 3 cracks and 1000 cracks are analyzed for demonstration.
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  • Tomoaki IWASAKI, Tetsuo IWAKUMA, Shigeru KOYAMA
    2002 Volume 5 Pages 273-282
    Published: August 28, 2002
    Released: March 17, 2010
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    The overall yielding behavior of anisotropic composites is affected by the hydrostatic pressure. A method to predict the overall elasto-plastic behavior of composites based on the Mori-Tanaka theory is expanded to examine the normality or the associativeness of the overall flow rule of composites quantitatively. A phenomenological constitutive model is used to evaluate approximately but quantitatively the hydrostatic-pressure effect on the subsequent yielding, and the results are compared with experimental data.
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  • Hitoshi MORITOKI, Hiroshi OIKAWA, Toshihiro OGINO
    2002 Volume 5 Pages 283-294
    Published: August 28, 2002
    Released: August 04, 2010
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    The volumetric change accompanying with plastic shear deformation causes the dependency of q on p where p and q respectively represent the hydrostatic pressure and equivalent deviatoric stress in yielding. Their dependency is called yield curve or yield function. For predicting yield curve the following assumptions are set up. Yield curves expand similarly in shape with plastic deformation and yield function plays as a plastic potintial. Basic yield curve is determined which gives a basic shape in similary expansion of yield curve. Using experimental results obtained under plane strain compression tests, we predict the basic yield curves. The basic yield curve has a limit over which yield curve cannot expand in (p, q) space. We call it expanding limit. First, it is examined whether plastic instability arises or not in plane strain compression tests, but its occurrence is denied consequently. Next, we show that multiple deformation rate can exist at the expanding limit. Hence, the onset of bifurcation is predicted at the expanding limit and the mode of shear plane is determined based on the concept of a characteristic plane. These predictions agree reasonably well with reported experimental observations.
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  • Yoshio TOBITA, Kenichi Kamo
    2002 Volume 5 Pages 295-306
    Published: August 28, 2002
    Released: March 17, 2010
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    The incrementally nonlinear behaviors of engineering materials, in particular geomaterials, are often reported and formulated into constitutive models. We here discuss the mathematical structure of incrementally nonlinear constitutive models among stress rates, strain rates, and the rate of change in internal variables through the representation theorem of isotropic functions and their matrix forms. As the examples of incrementally nonlinear models we discuss the formulation of the multi-slip model and the modified elasto- plastic model leading to incremental nonlinearity. Both models are evaluated whether they can account for the behavior of sands during the rotation of principal stress axes and found to be satisfactory from a qualitative view point.
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  • Shinji KONISHI, Takeshi TAMURA
    2002 Volume 5 Pages 307-316
    Published: August 28, 2002
    Released: March 17, 2010
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    For the shallow tunnel in sandy ground, an effect of drawing down of the ground water level for tunnel face stability is discussed in this paper. The effect was analyzed by means of rigid plastic FEA and Dupuit assumption. Using the numerical analysis, critical load factor was obtained and tunnel stability was evaluated. Drawing down of the ground water level makes relative gravity greater. In case of friction angle of ground material is greater than zero, the method is effective to increase the tunnel stability. Especially, it was confirmed that descending of ground water level from tunnel crown to spring line is the most effective to the stability.
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  • Hiroyuki MOTOYAMA, Kazumasa MORIYA, Satoshi KATSUKI, Toshiaki OHTA
    2002 Volume 5 Pages 317-327
    Published: August 28, 2002
    Released: March 17, 2010
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    Incrementaloading-reloading test on a CFRP stranded cable has been conducted under both twist free and twist fixed conditions. The effect on the tensile loading-reloading properties of CFRP cables twist confinement is investigated. The maximum tension capacity under twist free condition is 40% less than that under twist fixed condition. The electrical resistance of strand of CFRP cable along the fiber direction as well as the acoustic emission signals have been monitored during the test. The change of electrical resistance and the AE behavior are strongly correlated each other. It is suggested that the electrical resistance measurement could be effective for detecting of maximum load history of CFRP cable.
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  • Keisuke SATOH, Yuki YAMAKAWA, Kiyohiro IKEDA, Kunio TORII
    2002 Volume 5 Pages 329-338
    Published: August 28, 2002
    Released: March 17, 2010
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    In the compressive shearing test for geomaterials, various modes of localized deformation are observed. We carry out several bifurcation analyses by varying the shape ratio of plane strain rectangular specimens to observe the significant change of bifurcation loads and bifurcation modes. We also conduct a series of plane strain compression tests of soil specimens for various conditions to investigate the effect of the boundary conditions for the formation of the localized demormation modes. The numerically obtained bifurcation modes corresponding to the minimum bifurcation load for each size of the specimen are in good agreement with the typical experimental results for sand specimens.
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  • Teruo NAKAI, Masaya HINOKIO, Keisuke ARAMAKI
    2002 Volume 5 Pages 339-348
    Published: August 28, 2002
    Released: March 17, 2010
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    Generally localization of deformation is considered as boundary value problem in numerical analysis. Finite element analysis using soil-water coupling and finite deformation theory can express the shear band numerically. In this research, it is shown that the finite element analysis, using the constitutive model considering the influences of density and confining pressure, based on small deformation theory can express the localization of deformation for both the conditions of soil-water coupling and soil ground without water. Mechanism of development of the shear band is considered by investigating the behavior of each element.
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  • Tatsuro NISHIYAMA, Takashi HASEGAWA
    2002 Volume 5 Pages 349-356
    Published: August 28, 2002
    Released: March 17, 2010
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    The mechanisms of in-situ rock shear tests were investigated for the sake of constructing a theoretical method for the estimation of the strength of rock masses. Localized failure in the testing process was especially noticed, and it was treated with Mohr's failure criterion. The investigation consisted of experiments on gypsum models whose conditions were similar to those in in-situ rock shear tests and of stress analyses for these experiments. Theoretical interpretations of the characteristic cracking process and of the machanisms of the appearance of shear strength, measured by in-situ rock shear tests, were obtained from the results.
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  • Toshihide SHIBI, Takeshi KAMEI, Chikayoshi YATOMI
    2002 Volume 5 Pages 357-366
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    This paper investigates inhomogeneous deformation behavior of clay under the plane strain undrained extension loadings based on bifurcation theory. Constitutive equations of clay are applied for a coaxial and a non-coaxial Cam-clay model. Development locations and forms of slip surfaces are estimated based on distribution of maximum shear strain at the occurrence of bifurcation. Bifurcation stress ratios with lower symmetric modes are smaller under extension loadings than any other mode. The smallest bifurcation stress ratio under extension loadings is larger than the smallest ratio under compression loadings. However, bifurcation stress ratio in extension tests is smaller than in compression tests in the case of lower symmetric modes that the influence of the allowable eccentric load is small. Slip surfaces observed under compression loadings develop from the center of the inside to the side in the end face at top and bottom. In extension tests, however, slip surfaces develop from the exterior at the point of greatest narrowing to the inside.
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  • Masatoshi OUCHI, Fang-Le PENG, Junichi KANAIZUKA, Osamu KUSAKABE
    2002 Volume 5 Pages 367-376
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    In order to develop the rational numerical method for predicting the deformation and failure of the pier foundation on slope, a series of nonlinear elasto-plastic FEM analyses were conducted to simulate the field experiment on the bearing capacity and failure deformation of pier foundation on rock slope under the lateral loading. In the analyses, rock was supposed to obey an elasto-perfectly Mohr-Coulomb plastic material with or without considering no-tension effect The results obtained from the FEM analyses were compared with those from the field experiment It was found that the load-displacement relation of the pier foundation obtained from the 3D-FEM analysis with considering the no-tension effect has a good agreement with the field experimental result In addition, the plastic failure mechanism of pier foundation on rock slope could be well simulated by the 3D-FEM analysis with the no-tension model.
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  • Hisao TSUNOKAKE, Kazumasa WAKISAKA, Keiichiro SONODA, Harutoshi KOBAYA ...
    2002 Volume 5 Pages 377-384
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    This study is intended to investigate the shear capacity and shear failure mode of the concrete filled steel tubular (CFT) members with a large width-thickness ratio of steel plate. Six specimens used have a square cross section and 200 or 250 of width-thickness ratio of steel plate. The beam specimens simply supported were tested, in shear-span ratios ranging from 0.75 to 2.0, by a two-point loading method. Only the specimen with 0.75 of shear-span ratio showed a clear shear failure mode. The shear capacities of these specimens amounted to 4.61 times as large as the values predicted by the current codes of CFT members in which the shear capacity assumes to be yielded by only steel section. Discussions are made on the shearing rate of shear strength into steel section and core concrete. And it is suggested that the shear capacity of CFT member may exceed the simply cumulative strength of steel webs and core concrete by virtue of a confinement effect.
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  • Poologasingam Navakumar, Tatsuya Tsubaki
    2002 Volume 5 Pages 385-392
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    A numerical simulation model is presented for the analysis of a reinforced concrete beam under monotonic loading based on the finite element method. The present method has an advantage of taking into account the influence of diagonal cracks in addition to flexural cracks in concrete. After having a diagonal crack. the interval corresponding to the diagonal crack with the shear deformation mode is modeled by shear type elements. The stress transfer to the shear reinforcement from the concrete is expressed by this method. The applicability of the present model to a beam with shear reinforcement is discussed. The analytical result with the present model is compared with the test data as well as the design code.
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  • Mitao OHGA, Shinichiro TAKEMURA, Satoru IMAMURA
    2002 Volume 5 Pages 393-400
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    In this paper, the influences of round corners on axial compressive properties of the box-section members, such as, nonlinear behavior, yield and ultimate strength, and energy absorption capacity are examined by the finite element method. In this method, so-called 9-node isoparametric degenerated shell element with independent displacement and rotation degrees of freedom is used. The Green Lagrange strain definition and the Prandtl-Rcuss stress-strain relation following the von-Mises yield criterion are applied to incorporate the geometrical and material nonlinearity. The box-section members without longitudinal stiffeners are adopted as analytical models, in the numerical examples. The influences of round corners of cross section on axial compressive properties are examined with different sizes of the round corner radius.
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  • Seiichiro Tsutsumi, Koichi Hashiguchi, Masaya Sugimoto, Kiyohiro Ikeda ...
    2002 Volume 5 Pages 401-409
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    It is widely known that the principal stress directions rotates in foundations subjected to the cyclic loading due to wheel traveling, tidal wave, earthquake, etc. Besides, it has been indicated that the direction and the magnitude of inelastic deformation of soils depend on the stress rate much more than those predicted by elastoplastic constitutive equation with the smooth plastic potential surface. In this article the deformations in test results for sands subjected to the principal stress rotation process keeping the magnitudes of principal stresses and to the stress rates with various directions are predicted appropriately by the subloading surface model with the anisotropy due to the rotation of yield surface and the tangential stress rate effect which lead to the non-coaxiality of directions of inelastic strain rate and stress.
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  • Hidenori YOSHIDA, Mitsumasa WADA, Koji SAKAI
    2002 Volume 5 Pages 411-420
    Published: August 28, 2002
    Released: March 17, 2010
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    Nowadays, it is hoping for the room space with the spacious comfortableness in a public building, a office building, and a housing. Though a big span slab is proposed in order to solve such a issue, there are a lot of uncertainties for the mechanical behaviors of the slab. The uncertainties are arisen from loading condition, end restraint condition, initial condition, etc. Among them, the end restraint condition is noticed, and the numerical analyses are carried so as to evaluate its effect on the behaviors or RC slab. In this article, the effect is clarified through the non-linear analytical method in which tension-softening and compressive failure can be considered.
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  • Masao SATAKE
    2002 Volume 5 Pages 423-430
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    This paper intends to propose a new micro-mechanical definition of strain tensor for granular materials, using the Dirichlet (or modified Voronoi) tessellation defined for granular assemblies. Although another definition of strain tensor has been proposed up to the present, it is shown that the new definition has a lot of advantageous points, such as the good correspondence to the compatibility condition. Regarding the most general case, the micro-mechanical definition is also given for couple stress and rotational strain. For the inner work in granular materials, it is shown that the proposed strain satisfies the Hill's condition in a modified and radical form. To clarify the necessity of the micro-mechanical strain, three kinds of simple shear deformation, which are same macroscopically but different micro-mechanically, are analyzed using the proposed strain definition.
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  • Naonori KUWABARA, Ryougo OHNO, Kenichi MAEDA
    2002 Volume 5 Pages 431-440
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    Granular material shows non-linear deformation behaviors depending on density and over-consolidation histories. The evolution and collapse of microstructures formed in granular material control the macro behaviors. In this paper, the density and over-consolidation dependencies of deformation-failure behaviors were calculated by DEM in two-dimensional test. The geometric parameters such as fabric tensor described for stress-induced anisotropy and coordinate number, evolutions of stable microstructures and mobilization of rotation resistance around particles, were investigated. On the basis of analysis results, it was revealed that the collapse of stable structure during macro deformation induced the macro failure and the dependencies of density and over-consolidation were controlled by the mobilization of rotation resistance due to particle shape effects.
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  • Kenji KANEKO, Tateki ISHII, Wataru NARUMI, Yuji KISHINO
    2002 Volume 5 Pages 441-450
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    We discuss the plastic flow of granular media performed under the principal stress axes rotation with the aid of numerical experiments. A series of numerical tests consists of the shear tests and the stress probe tests using a 3-dimensional Granular Element Method. We examine incremental plastic strain response under the principal stress axes rotation in detail after determining parameters for simulations by comparing shear test simulations with experimental results in literature. In particular, on the incremental non-linearity of the plastic strain increment, we discuss the similarity between real experiments and simulations, as well as the mechanism of the nonlinearity.
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  • Tateki ISHII, Kenji KANEKO, Yuji KISHINO
    2002 Volume 5 Pages 451-460
    Published: August 28, 2002
    Released: March 17, 2010
    JOURNALS FREE ACCESS
    As a generalized constitutive relationship for granular media, incrementally non-linear models have been proposed by many researchers. However, it is hard to evaluate the validity of such constitutive models in terms of experiments on real materials. On the other hand, the discrete element simulations have the capability to solve this problem. In this paper, true tri-axial stress probe tests were simulated in terms of 3D numerical discrete element method. The results suggests that the exact behavior of granular media have to be described by a model with incremental non-linearity. The stress probe test result is compared with recent constitutive theories and the mechanism of the incremental non-linearity is discussed as well in terms of an eigenvalue analysis.
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