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Published: August 22, 2001
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Published: August 22, 2001
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Article type: Appendix
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Published: August 22, 2001
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Published: August 22, 2001
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Published: August 22, 2001
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Article type: Index
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Published: August 22, 2001
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Kiyoshi MIZOHATA
Article type: Article
Session ID: K-0301
Published: August 22, 2001
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This paper describes a new method for image compression which is based on multiwavelets. In 1994, Geronimo, Hardin and Massopust constructed a very important multiwavelet system. This system consists of two scaling functions and two wavelets. The scaling functions are both symmetric, and one of the wavelets is symmetric and the other is antisymmetric. Moreover, they each have compact support. In this talk we present a new preprocess of image data which decrease mean-square error of image compression based on multiwavelets.
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Masatake KAWADA
Article type: Article
Session ID: K-0302
Published: August 22, 2001
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Electroencephalogram (EEG) has been generally known as a non-destructive method to examine the function of human brain. This paper presents identifying time frequency components of human Movement-Related Cortical Potential (MRCP) accompanying with the human voluntary muscle behaviors using Wavelet Transform. The EEG was recorded with the 5-channel referential derivations, Fz, Cz, C3, C4, Pz, referenced to the right earlobe based on the international 10-20 system. The voluntary activity was recorded with the electrode arranged on the palm side of the metacarpophalangeal joint when the subjects flexed the right-hand index finger and eyes closed. About 10 Hz signals were recorded at all electrodes when the voluntary activity started. The higher level signals of about 10 Hz were recorded at Fz from about 0.4s after the activity started. About 5Hz signals appeared from about 1.0s to 0.2s at all electrodes before the activity started. This method isn't needed many trials to identify the components of the MRCP.
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Keisuke ARAKI
Article type: Article
Session ID: K-0303
Published: August 22, 2001
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Using orthonormal, divergence-free wavelets, which is given by unitary trasform of complex helical waves, we analysed a homogeneous, isotropic turbulence data obtained by a direct numerical simulation. Three-dimensional wavelet analysis requires such novel representations of wavelet spectra that represents the spatial location and amplitude, so we developed the ball representation of spectrum. Ball representation of wavelet spectrum reveals that kinetic energy of turbulence transfers not only to the small scales but also to the larger scales with almost same order of amplitude, i.e., backscatter phenomena actively occurs.
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Iwao OHTSU, Masaya Kondo, Taisuke YONOMOTO, Yoshinari ANODA
Article type: Article
Session ID: K-0304
Published: August 22, 2001
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The laser doppler velocimeter (LDV) using an optical fiber probe is advantageous to avoid hydraulic interactions between a bubble and the probe, compared with other probe-based methods. The typical response of the LDV probe was investigated by measuring the velocity of an air plug rising in water in a vertical pipe (I.D. 10 mm). Measured data was compared with the air plug velocity measured from VTR images taken at 13500 frame/s. The doppler signal analysis by using the Wavelet-transformation clearly indicated that the measured velocity tended to decrease steeply as the bubble came into contact with the probe, after showing a constant velocity. This finding indicates that it is necessary to discard the data obtained in the proximity of the probe in order to obtain the true velocity.
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Kousuke Seki, Yoshiyuki Tsuji, Masaya Kondo, Yutaka Kukita
Article type: Article
Session ID: K-0305
Published: August 22, 2001
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Parasitic capillary ripples generated on the forward face of the gravity-capillary waves are investigated experimentally. Using the optical technique, the slope angle of the wave is measured with sufficient space and time resolution to characterize the small ripple fluctuations. The ripple generation and its steepness is considered from the point of dominant wave asymmetry. Orthogonal wavelet transform is adopted to separate the small motions from the dominant waves, and the energy containing ratio is computed to discuss the ripple growth rate as a function of distance from the wave maker.
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Hirotsugu INOUE, Suguru YOKOYAMA, Kikuo KISHIMOTO
Article type: Article
Session ID: K-0306
Published: August 22, 2001
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A method of inverse analysis for indirect measurement of impact force is studied. The relationship between the impact force and response of a body is modeled by linear convolution. The impact force can be estimated by deconvolving the impulse response function from the measured response. The impact force is decomposed by the wavelet transform using Gabor wavelet in order to apply regularization using the singular value decomposition to each time-frequency component. It is found that the regularization parameter can be optimized by minimizing the norm of the residual of algebraic equation in terms of the wavelet coefficients of the impact force.
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Arata MASUDA, Akira SONE, Osamu SUGIYAMA, Yuito HASHIMOTO
Article type: Article
Session ID: K-0307
Published: August 22, 2001
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The earthquake motion is a non-stationary process in which the spectral content can change with time. Thus, when we simulate the input earthquake motion for the earthquake-proof structural design, the changing spectral characteristics of the earthquake should be taken into account. In this study, we try to generate simulated earthquakes which have the desired velocity response spectrum as well as the desired time-frequency characteristics. First, we show that the velocity response spectrum at a specific period can be interpreted as the maximum amplitude of the wavelet transform in which the velocity impulse response function is used as the analyzing wavelet. Using this relationship, the wavelet transform of the desired earthquake motion can be generated by an iterative scheme. Then the earthquake motion is obtained by taking the inverse wavelet transform of it.
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Sachiko NAKAGOSHI, Hirohisa NOGUCHI
Article type: Article
Session ID: K-0309
Published: August 22, 2001
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A new wavelet Galerkin Method for Mindlin plates is proposed. The wavelet Galerkin method is used to solve partial differential equations. In order to avoid shear locking, which is the phenomenon that the overstiff response is estimated under the Kirchhoff constraint condition in the very thin plate, the proposed formulation of wavelet Galerkin Method utilizes the B-spline scaling function for the approximation of transverse displacement field and the direct derivative of B-spline function for rotational field. As results, completely locking free responses are always obtained and the validity of the present wavelet Galerkin Method is clarified.
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Noriyoshi KUMAZAWA, Yasuyoshi FUKUI, Hiroshi OKADA, Ryosuke ESAKI, Kaz ...
Article type: Article
Session ID: K-0310
Published: August 22, 2001
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Semi-melt forming of functionally graded material (FGM) was investigated to identify the optimum operating temperture. In this paper, we applied online wavelet analysis to the device, and detected a discontinuity of deformation of FGM with temperature increase. The idea was confirmed to be suitable from microstructual observation. We developed a useful semi-melt forming system for refining micro-structure of FGM, which implove of mechanical properties.
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Toru TAKAHASHI, Naoshi NISHIMURA, Shoichi KOBAYASHI
Article type: Article
Session ID: K-0311
Published: August 22, 2001
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In this article, we propose a fast boundary integral equation method (BIEM) for elastodynamic problems in 3D in time domain by extending the formulation for 2D problems developed by present authors recently. In order to obtain a fast solution method, we need to construct a fast algorithm for evaluating the layer potentials in BIE and combine it with an iterative solver for linear algebraic equations. As in 2D problems, we construct the fast algorithm using the plane wave expansions of the single and double layer kernels for elastodynamic problems and the hierarchical system of time-space domain. The fast method obtained here is expected to reduce the computational costs from O(N^2_S N^2_t) required for conventional BIEM to O(N_Slog^2N-S N^2_t) and to solve very large scale initial-boundary value problems where N_S and N_t are the spatial and temporal degrees of freedom, respectively.
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Yoshitsugu KAWAKAMI, Ryuji ENDO, Nobuyoshi TOSAKA
Article type: Article
Session ID: K-0312
Published: August 22, 2001
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This Paper is coupled free vibration analysis of a large scaled floating plate model which is floating on sea of finite depth. The boundary value problem to obtain the coupled eigen value is formulated based on the interaction between elastic beam and fluid. The Vibration equation governing the motion of coupled system is derived by a Finite-Boundary Element Combined Method and solved by a Determinant-Search procedure. In this study, numerical examples are presented for the mat type floating plate.
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Eisuke KITA, Jun'ichi KATSURAGWA, Norio KAMIYA
Article type: Article
Session ID: K-0313
Published: August 22, 2001
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This paper describes the application of the Trefftz method to the simulation of the sloshing phenomenon. The phenomenon can be modeled as the initial and the boundary value problems with respect to the Laplace equation. The equation is solved to determine the velocity and the acceleration components on the fluid surface. For solving the initial value problem, we will compare the simple Euler scheme using velocity vector on the free surface alone and the extended scheme using both velocity and acceleration. Finally, the present scheme is applied to the simulation of the sloshing phenomenon on the fluid in a rectangular vessel.
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Masataka TANAKA, Toshiro MATSUMOTO, Yusuke SUDA
Article type: Article
Session ID: K-0314
Published: August 22, 2001
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This paper presents a dual reciprocity boundary element method (DRBEM) for solving the steady-state heat conduction problems of inhomogenerous materials. The integral equation formulation uses the fundamental solution of Laplace differential equation for a homogeneous material, and hence a domain integral arises in the boundary integral equation. This domain integral is transformed into a boundary integral by using a new set of radial basis functions. The details of the proposed DRBEM are presented, and a computer code is developed for three-dimensional problems. Numerical computation is carried out for several examples, the exact solutions of which are available in the literature. Through comparison of the results obtained by the computer code with the exact ones, the potential usefulness of the proposed DRBEM is demonstrated.
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Nobuyoshi TOSAKA, Yoshihiro OCHIAI
Article type: Article
Session ID: K-0315
Published: August 22, 2001
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A possibility on application of the boundary solution method to nonlinear problems described with differential equation is discussed. Especially, a solution procedure in the boundary integral equation in solving approximately nonlinear problems is proposed with use of the multiple reciprocity method which was introduced in order to transform the domain integral to the boundary integral. The stringer approximation procedure in the multiple reciprocity method is developed in the equation of large deflection problem of an elastic cantilever beam.
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Toshiro MATSUMOTO, Masataka TANAKA, Atsushi NAKAHARA
Article type: Article
Session ID: K-0316
Published: August 22, 2001
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Java is used to develop a boundary element code for two-dimensional potential problems. In the boundary element method, the coefficient matrix of the final system of linear algebraic equation is calculated by repeating the evaluation of the boundary integral over each element for a collocation point of the fundamental solution. Since these integrations can be evaluated independently, the boundary element method is suitable for distributied parallel computation. Java is an object-oriented programing language with various class libraries for network computing and its message passing is used for developing a boundary element code in which evaluation tasks for boundary integrals are distributed to sub-programs running on PCs connected through the internet.
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Yoshihiro OCHIAI
Article type: Article
Session ID: K-0317
Published: August 22, 2001
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This paper presents a three-dimensional numerical singular integration by using the boundary integral equation and the polyharmonic function. In the method using B-spline, points must be assigned in a gridiron layout. In the presented method using polyharmonic function, arbitrary points can be assigned instead of a gridiron layout, therefore it becomes easy to integrate. This method requires a boundary geometry of the region and arbitrary internal points. The integral value are calculated after solving the discretized boundary integral equations.
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Hideo KOGUCHI, Masahiro YOSHIKAWA, Susumu YAMASHITA
Article type: Article
Session ID: K-0318
Published: August 22, 2001
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Recently, surface mount technology (SMT) in a microelectronic packaging is playing a leading role compared to the plated-through-hole technology. Many investigations on SMT have been conducted numerically and experimentally. Thermal stress analysis is needed for evaluating the reliability of solder joints. At that time, it is very important to know the domain shape for analysis, although it is usually difficult to measure in situ the profile of SMT solder joints mounted on the base plate. In the present paper, the three-dimensional shape of solder joints is determined numerically by employing a multi-zone BEM, where the surface tension of molten solder and gravity are considered. The joint profile varying from an initial profile to an equilibrium one is simulated using a finite difference scheme for time and the boundary element method for domain.
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Masataka TANAKA, Toshiro MATSUMOTO, Hironori YAMAMURA
Article type: Article
Session ID: K-0319
Published: August 22, 2001
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This paper concerns application of an inverse analysis method for identification of unknown parameters corresponding to load, and material constants of an elastic plate. An extended Kalman filter and the boundary element method are applied to the inverse analysis. The numerical results obtained are discussed. The extended Kalman filter algorithm can estimate state variables of a stochastic system. It is expected that the algorithm is also applicable to analysis of other identification problems for which noisy data are available at some measuring points.
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Hideo KOGUCHI, Takefumi Imai
Article type: Article
Session ID: K-0320
Published: August 22, 2001
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In electronic devices, such as semiconductor devices and magnetic recording devices, there are many devices with structures which a single layered or multilayered of metallic or polymeric thin films are coated on the substrate. The thin films may be delaminated from a substrate by contacting with dusts and other mechanical device. In this study, an intermolecular force, Van der Waals force, is introduced into the fundamental mechanism of adhesive force. A Boundary Element Method (BEM) is used for analyzing the delamination of thin film. The thin film is pushed up using an indenter from the substrate. As the results, the behavior of thin film and substrate in the delamination process of thin film was simulated and the force required for delaminating the film was examined.
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Kenji Amaya, Shigeru AOKI, M Ridha
Article type: Article
Session ID: K-0321
Published: August 22, 2001
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An inverse analysis method was developed for identifying a small corrosion of a rebar in concrete structure. In this method, Location of the corrosion was estimated from some magnetic flux densities instead of potentials which were measured on the structure. The BEM was employed to solve the Laplace equation which models the potentials in the structure. The corrosion current associated with a magnetic field is well known. The use of magnetic flux density measurement could improve the accuracy of the inverse analysis method, because a very low magnetic flux intensities could be detected by employing the SQUID sensor which has a very high magnetic field sensitivity. An example using a numerical simulation data was used to demonstrate the effectiveness of the proposed method.
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Toshimitsu FUJISAWA, Genki YAGAWA
Article type: Article
Session ID: K-0322
Published: August 22, 2001
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A parallel distribution technique of computing loads for compressible flow analysis is presented. In the present method, the optimal assignments of computing loads are obtained in a parallel way on any number of processors, by employing a graph partitioning library, parMETIS. The method is applied to a model of wind tunnel with a step, and it is confirmed that the number of 'independent nodes' in the NBN-FEM becomes substantially large by the parallel renumbering operations.
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Hiroshi OKUDA, You Muraki, Genki YAGAWA
Article type: Article
Session ID: K-0323
Published: August 22, 2001
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Software-integrated environments for using GeoFEM, which is a parallel FE program on Unix, has been developed. In the course of CAD modeling through post-processing, in addition to GeoFEM, users need to use various type of applications, which run on Windows or Unix. 'GeoFEM controller', which is a Windows application developed in this study, utilizes the message-hook procedure for making 'GeoFEM controller' control Windows applications of which source codes are not given. For controlling Unix applications from 'GeoFEM controller', the keyboard-events are sent to the terminal program such that the desired users' inputs are transmitted to Unix applications.
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Hiroshi Okuda, Shin'ichi Ezure
Article type: Article
Session ID: K-0324
Published: August 22, 2001
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The finite elements are widely applied in various fields of engineering sciences. For large-scale problems, iterative methods are normally implemented to solve a set of discretized linear equations. However, it is known that the convergence rate declines as the iteration loop is processed. Geometric multigrid methods are known to increase this convergence rate by implementing mesh data at several levels. At the same time, in order to carry out computer simulations of complex large-scale problems, parallel computers are necessary to store huge amounts of data and to solve such a problem in a given practical time. In the past, the authors have reported a tool called the Parallel Mesh Relocator which combined the functions of partitioning and refining of a given finete element mesh. In this study, an algorithm is reported which tightly couples this PMR and multigrid solver, enhancing the large-scale parallel finite element analyses.
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Hiroshi OKUDA, Masataka SUGIYAMA
Article type: Article
Session ID: K-0325
Published: August 22, 2001
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This paper describes that our studies puts emphasis on the load imbalance problem in heterogeneous computing environment as PC cluster. The PMR (Parallel Mesh Relocator) which combines the function of partitioner and the mesh generator was developed. The PMR aims at the provision of tools to achieve load balancing for large-scale parallel finite element method analysis on homogeneous computing environment. Therefore, it is brought about the load imbalance for different computer performance and communication. Then, this research confirms validity by performing the efficient processing effect in heterogeneous computing environment by introducing the process (DRAMA) of the load distribution which performs cost evaluation and re-partition of an element to a parallel finite element method.
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Keishin TANIGAWA, Chuichi ARAKAWA
Article type: Article
Session ID: K-0326
Published: August 22, 2001
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These days, CFD simulation generates enormous output data, as a simulation handle large scale and complicated phenomenon. In this paper, we try to show a fluid phenomenon with so called "particle path". Each particle has information such as a coordinate, a velocity and a pressure. A particle updates the information by searching the nearest grid point, and moves the coordinate to updated velocity. We actually apply this visualization method to show a wind flow. Generate some particles dynamically, then observe the particle motion. Now we expect that we can show this application on CABIN, and we improve various input method to show phenomenon effectively.
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Qun ZHANG, Toshiaki HISADA
Article type: Article
Session ID: K-0327
Published: August 22, 2001
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Coupling methods for fluid-structure interaction analysis can be classified into the strong coupling methods, the weak coupling methods, and the constraint methods. Although the strong coupling methods show excellent convergence rate in many problems, the overall modification of the programs for fluid analysis and structural analysis is required. The weak coupling methods are, therefore, more practical if their performances can be improved. In the present paper, the weak coupling methods are classified into three groups, and the consistent added matrices derived from the strong coupling equations and their approximations are systematically presented. Through numerical examples, their capabilities and computational efficiencies are compared.
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Hiroshi FUKUNARI, Qun ZHANG, Toshiaki HISADA
Article type: Article
Session ID: K-0328
Published: August 22, 2001
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Systole and diastole of a human heart are simulated by FSI finite element method. Heart muscle is assumed to be hyper-elastic material. ALE finite element method is employed for blood fow analysis. A strong coupling method is used to cope with strong interaction between the fluid and the structure. Shrinking force of heart muscle is introduced by the initial strain for the muscle solid elements. A numerical result of a simplified left ventricle model is given to demonstrate the capability of the newly developed FSI program.
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Tetsuhiro Kawamura, Qun ZHANG, Toshiaki HISADA
Article type: Article
Session ID: K-0329
Published: August 22, 2001
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Pulsation of a blood pump of totally implantable artificial heart is simulated in this research. A finite element mesh for the complex model isgenerated by the Laplace-equation based mesh moving algorithm. ArbitraryLagrangian Eulerian (ALE) finite element formulation is employed for thefluid, and the generalized conforming flat shell element is used for thegeometrically nonlinear analysis of the diaphragm. The strong coupling method and some stabilization techniques are used in order to cope with thestrong dependence between the fluid and the structure.
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Yoshiaki KOINUMA, Noboru TOMIOKA, Akifumi OKABE
Article type: Article
Session ID: K-0330
Published: August 22, 2001
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We propose the methods to apply the EFGM (Element Free Galerkin Method) developed by T. Belytschko et al. to the stress analysis of Adhesive Butt Joints, and analyzed the interface stresses in the three-dimension. We divide the model of analysis to the domain of the same materials as Material1, Material2 and Adhesive, and applied the EFGM to Material1, Material2 and Adhesive respectively. Then, each displacement of Materiall and Material2 must be continuity on interface. So we restrain the displacements on the interface by the penalty method.
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Changcheng SHAO, Yasuhiro MATSUDA, Masato Yoshino
Article type: Article
Session ID: K-0332
Published: August 22, 2001
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The Element-Free Galerkin Method is applied to the numerical analysis for two-dimensional viscous fluid flows of high Reynolds numbers. An elliptic domain of influence is used for a node disposition of high aspect ratio. The driven cavity flow problems are solved up to the Reynolds number of 10,000. Steady solutions are obtained, which agree well with Ghia's.
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Tetsuji Ichikawa, Toshikazu Torigaki
Article type: Article
Session ID: K-0333
Published: August 22, 2001
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A direct elimination scheme is presented for the solution of large scale voxel vibration analysis. The regularity of the stiffness matrix of the voxel models is used for decision of the order of elimination. By this process, elimination of degrees of freedoms can be performed without storing all non-zero profile of the global coefficient matrix. Sample solutions verify that large-scale voxel models can be analyzed with the smaller amount of in-core memory and out-core device storage.
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Toshihiro KOMURA, Noriyuki MIYAZAKI, Toru IKEDA
Article type: Article
Session ID: K-0334
Published: August 22, 2001
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Takeshi Kawamoto, Takeshi Iwamoto, Toshio TSUTA
Article type: Article
Session ID: K-0335
Published: August 22, 2001
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The transformation-induced plasticity (TRIP) steel possesses such favorable mechanical properties as tenacity and strength due to strain-induced martensite transformation. This excellent mechanical properties of TRIP steel depend on inhomogenious morphology of martensite in microscopic region. However, to evaluate the effect of microscopic morphology of martensite on its mechanical properties, it is difficult to express microscopically its heterogeneous deformation behavior by a conventional FEM. Here, the computational simulation of deformation behavior of TRIP steel is performed by recently developed homogenization method.
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Shinji KUBO, Takeshi IWAMOTO, Toshio TSUTA
Article type: Article
Session ID: K-0336
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Recently, the low alloy and high strength steel which improved TRIP steel is developed. Its application for the impact absorbing parts of an automobile is considered. However, the effect of strain-induced martensitic transformation on the impact energy absorbing characteristics of TRIP steel is still unclear. Here, the impact energy absorbing characteristics of TRIP steel and the influence of strain-induced martensitic transformation on the impact deformation behavior are evaluated by dynamic-explicit elasto-viscoplastic FEM.
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Hiroshi OHYA
Article type: Article
Session ID: K-0337
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The finite element method is applied to the nonlinear buckling analysis of laminated composite shells of revolution under axisymmetric loading. The displacement field within each element is represented by Fourier circumferential components. The symmetric and antisymmetric Fourier terms are considered. The coupling effect of general laminates is considered in the stress-strain relation. The effect of displacement field on buckling load is investigated.
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Tadashi KOBAYASHI, Nobuhiro SUGIMURA, Yoshihiro OCHIAI, Narihei KAWASH ...
Article type: Article
Session ID: K-0338
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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A combined model of FEM and BEM is proposed by using the concept of the Rigid-Body Spring Model. The new model is formulated for axisymmetric problems and applied to the elastic contact problems. The numerical examples show that the simple boundary elements proposed here are effective for contact problems.
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Takuya UEHARA, Masanori KAWAHARA, Tatsuo INOUE
Article type: Article
Session ID: K-0339
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Dendritic crystal growth process is simulated by use of phase-field model. The formula of the phase-field model is based on two fundamental equations, phase-field equation and heat conduction equation, when a monocomponent system is considered. Those equations are summarized in this paper without detailed explanation, since they are introduced in other references. The factors which affect the morphorogy of the crystal are latent heat and anisotropy, both of which are taken into account in the equations by corresponding functions and parameters. In this study, the anisotropy of the interface energy and kinetic coefficient are evaluated by molecular dynamics simulation to introduce the parameters in the phase-field model. The shape of the crystal in the initial stage, facet-type or dendrite-type, is revealed to much depend on the anisotropy parameters.
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Takanori Ogawa, Fumiyasu Kubo
Article type: Article
Session ID: K-0340
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This paper reports on the development of combination analysis of a three-dimensional fluid dynamics and structure around a mixing valve with SMA (shape memory alloy) coil. A mixing valve with SMA coil automatically controls the mixed water temperature with SMA coil. However we can not simulate the phenomenon with a simple computational fluid dynamics, because the movement of valve brings the transition of fluid shape. Furthermore it is a nonlinear phenomena such as vibration of the valve. We calculated one problem to test this module. We described the whole aspect of combination analysis of fluid dynamics and structure and present the results of this calculation.
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Misuk YAMAZAKI, Masaki TSURUKI, Takasi MACHIDA, Makoto KITANO, Naoto S ...
Article type: Article
Session ID: K-0341
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Reliability evaluation system for efficient design of mechanical structure has been developed. This system is based on Finite element sensitivity analysis (FESA) for coupled problem that is concerned with both heat conduction and thermal stress analyses. A new formulation for this coupled analysis in FESA has been derived. This developed system has been applied to the design of a turbine blade. As a result, it is shown that the fluctuation of responses to that of all design parameters is recognized by one analysis result in this system.
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Hideki AOI, Masashi MATSUURA, Kunio FUNAMI, Hiroyuki MIYAMOTO, Yue ZHA ...
Article type: Article
Session ID: K-0342
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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This report describes a newly developed cascade impacter pollen collection device. We performed an adhesion experiment using alder pollen, and found the results to be in close agreement with the results predicted by a numerical analysis based on the Navier-Stokes equation and the Euler-Lagrange method. Based on this airflow method, we analyzed the separation of four typical Japanese pollens under various conditions of air suction velocity and nozzle diameter. Pollen grains are collected in four stages of the device. To separate pollens adhered to the same plate, we used an automatic pollen measuring system, which allowed pollen grains to be completely separated.
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Yasunori Masunaga, Jae-Il Kim, Toshio Sakuma, Kazuo Murata, Shuichi Mi ...
Article type: Article
Session ID: K-0401
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Since the resistance welding technique is widely applied for joining in several metals and alloys, this may be also applicable for Ti-Ni alloys. It is also known in Ni-rich Ti-Ni alloys that the shape memory and mechanical properties depend on heat-treatment through microstructural change. In this study, the resistance-welding was applied for Ti-50.9at%Ni alloy wires with 1mm in diameter. In order to clarify the effect of heat treatment, various heat treatments were performed before and after the resistance welding. Mechanical characteristics such as fracture stress and strain were investigated by tensile tests. The fatigue life was evaluated using rotary-bending fatigue tests. Microstructural observation for welded zone and heat affected zone (HAZ) was also carried out by optical microscope and transmission electron microscope (TEM). It was found that the fracture stress of some resistance-welded wires exceeded 1GPa. Optical microscope and TEM observation revealed that microstructure near welded zone was affected by heat treatment, resulting in change of mechanical properties.
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Maho Hosogi, Toshio Sakuma, Nagatoshi Okabe, Uichi Iwata, Shuichi Miya ...
Article type: Article
Session ID: K-0402
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Repeated uses of shape memory alloy cause the functional degradation. The changes in the function appear depending on cyclic conditions. In this paper, the effects of cyclic use on the change in the transformation temperature were investigated for a Ti-40Ni-10Cu(at%) shape memory alloy. After thermo-mechanical and superelastic cycle tests were carried out, the changes of each transformation temperature were measured using the DSC. Results show that the changes in the transformation temperatures can be estimated unificationally using the accumulated strain energy, which can be defined as the total decrease of recovery strain energy, regardless of cyclic modes. Formulated the change in the accumulated strain energy as a function of cyclic number and maximum strain, the transformation temperatures can be predicted for any cyclic numbers.
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Makoto Yamada, Toshio Sakuma, Uichi Iwata, Yasuo Ochi, Takashi Matsumu ...
Article type: Article
Session ID: K-0403
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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The deformation behavior of Ti-Ni shape memory alloy coil spring was investigated using loading-unloading cycling tests under fixed temperatures. And the effect of Ni content and shape memory treatment temperature on superelastic function was investi gated. The deformation behavior within elastic region of parent phase did not almost change during tensile cyclic loading. However, when the martensite phase was induced by stress, the deformation behavior changed largely. The critical shear stress for inducing martensites and the dissipated strain energy per unit volume decreased with increasing number of cyclic loading. The functional degradation depended on the Ni content and the shape memory treatment temperature, and increased with decreasing Ni content and increasing shape memory treatment temperature.
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Shinji ISOKAWA, Makoto OHTSUKA, Minoru MATSUMOTO, Toshiyuki TAKAGI, Ki ...
Article type: Article
Session ID: K-0404
Published: August 22, 2001
Released on J-STAGE: August 01, 2017
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Ferromagnetic shape memory alloy Ni_2MnGa has Heusler type crystal structure. Cubic structure of high temperature phase transforms to tetragonal one during cooling by thermo-elastic martensitic transformation. These transformation temperatures are below Curie temperature. Curie temperature decreased and transformation temperatures increased with increase of Ni composition in non-stoichiometric Ni_<2+x>Mn_<1-x>Ga (x=0〜0.19). Sputtered films were fabricated by a magnetron sputtering apparatus. The thickness of these films was 5 μm. Columnar structures which grew in parallel with the thickness of film were observed in these films. Crystal structures, transformation temperatures and magnetic properties of these films were similar to bulk specimens. Sputtered films showed two way shape memory effect.
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