This paper deals with an inverse problem for estimating the magnitude of the residual stress in a butt-welded plate from measured data This paper uses Tikhonov's regularization to improve the accuracy of the estimated values of the inherent strains in the butt-welded plate. Numerical simulations were conducted for an analysis model which was the same with that used in the previous paper. The inherent strains in the butt-welded plate were estimated from a few measured stresses with measurement errors using Tikhonov's regularization. The discrepancy principle was applied for estimating a proper value of the regularization parameter. It was found that Tikhonov's regularization and the discrepancy principle were usefi.il in estimating the residual stress in the butt-welded plate.

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Service conditions and structures of gas turbines are so complex that it is very difficult to determine boundary conditions for thermal-mechanical analyses of the gas turbines. To improve the accuracy of the analyses, an analytical method for estimating the service boundary conditions for the whole gas turbine stator has been developed. This method consists of FEA (finite element analysis), design of experiments, and measured metal temperatures in an actual gas turbine. The FEAs varied with boundary conditions are analyzed using an orthogonal array. In each analysis, difference between results of an FEA and measured results are estimated. The model is modified to reduce the difference by using analyses of variance iteratively. The method was applied to a 150kW micro gas turbine stator and the good agreement between the analysis results and the measured data confirmed the validity of the method. The modified model is applied to maintenance planning and life assessment of the gas turbine.

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This paper proposes a method of inverse analysis for identification of an impact load using selected strain data. Taking the dynamic behavior of structure under the impact load is comparatively easy if many sensors and high precision measuring devices are available. On the other hand, if the dynamic behavior can be identified by a few strain data with lower accuracy, the method has advantages to measuring cost and efficiency. In our proposed inverse analysis, the fuzzy clustering is used for selecting and picking up the strain data containing error for the neural network learning. As a result, it is shown that the proposed method using fuzzy clustering has an advantage on the inverse analysis for some margin of error.

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This paper presents the free vibration analysis of FRP laminated composite plates with damping sheets. For this purpose, the governing equations are formulated for a cross-ply laminated, simply-supported rectangular plate based Discrete-Layer Theory (DLT), Higher-order Shear Deformation Theory (HSDT) and Classical Lamination Theory (CLT), respectively. In the numerical examples, natural frequencies and specific damping capacities are calculated numerically for the plates with different damping sheet thickness by assuming complex elastic modulus. Finally the applicability of each analytical model for damped vibration analysis is studied by comparing with numerical results obtained respectively.

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This paper studies the evaluation of damped free vibration characteristics of FRP laminated composite plates. For this purpose. the strain energy and the kinetic energy are formulated for the rectangular plate based on Discrete-Layer Theory (DLT). Higher-order Shear Deformation Theory (HSDT) and Classical Lamination Theory (CLT). respectively. The frequency equations are derived for the plate freely-supported at all edges by using the Ritz's procedure. In the numerical examples, natural frequencies and specific damping capacities are calculated numerically for the plates by assuming complex elastic modulus. Natural frequencies and modal damping ratios are also obtained experimentally by experimental modal analysis. Finally the applicability of each analytical model for damped vibration analysis is studied by comparing with numerical and experimental results.

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In this study X-ray CT image is used for meso-scale surface modeling of irregular shaped gas pores in aluminum die cast alloy, followed by image based finite element analysis to evaluate crack initiation point. There is a good agreement between the location of maximum principal stress found by the analysis and location of crack initiation on actual fractured surface. We conclude that mesa-scale image based finite element method is promising for fatigue life prediction of aluminum die cast alloy.

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Creep crack growth behavior often needs to be predicted in evaluating structural integrity of components operated at high temperature. Although finite element method can be used for its simulation, various difficulties arise due to high nonlinearity and history-dependency of creep deformation. This paper presents several problems encountered in finite element analysis of creep crack growth and discusses possible solutions after showing a typical example of analysis.

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In this study. numerical models have been developed to simulate the competition between short crack propagation and wear in rail head. The locations of crack initiation are given by a random generator in the pro-eutectoid ferrite at the beginning of the simulation. The crack is assumed to initiate when the total accumulated plastic shear strain in the region reaches the critical shear strain value. The growth of Stage I short crack occurs along the ferrite and pearlite boundaries. If the crack becomes long enough to open its faces, Stage II short crack growth is assumed to occur. In these crack growth simulations, Hobson law is applied. With regard to wear, the Archard model is adopted as the basis. The wear depth can be calculated from the normal pressure distribution in the wheel-rail contact region, the sliding distance etc.

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Photon-phonon interaction on the analogy of electron-phonon interaction is considered in one-dimensional metal photonic crystal. When lattice vibration is artificially introduced to the photonic crystal, a governing equation of electromagnetic field is derived. A simple model is numerically analyzed and the following novel phenomena are found out. The lattice vibration generates the light of frequency which added the integral multiple of the vibration frequency to that of the incident wave and also amplifies the incident wave resonantly. On a resonance, the amplification factor increases very rapidly with the number of layers increases. Resonance frequencies change with the phases of lattice vibration. The amplification phenomenon is analytically discussed for low frequency of the lattice vibration and is confirmed by numerical works.

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In this paper, the effects of the thermal stress on the elastic wave propagation in phononic crystals are investigated. Based on the Bloch theory and the plane wave expansion method, the expression of the generalized eigenvalue equation is derived. The band structures for the in-plane and out-of-plane modes are presented. The results show that the filling ratios corresponding to the maximums of the band gap for the in-plane mode and mode II of the out-of-plane mode are different. The band gap characteristics can be changed by the thermal stress. The larger the temperature variance is, the lower the band gap edges become.

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A simple and eflicient computational model by using multibody dynamics is presented to solve the dynamic behavior of ballast in the railway track. The geometry of a crushed stone in the ballast is defined by a triangular patch of the boundary surface. A simple mechanical model to express the contact-impact behavior among crushed stones and sleeper in the bailasted track is eseribed. Based on the present method, a computer program has been developed for the dynainicanalysis of a ballasted track. Some examples are demonstrated.

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For years the sandwich structure such as Truss Core Panel and Honeycomb Panel has enjoyed popularity in vehicle applications because of its extremely high structural efficiency that is light weight and high stiffness. Since the stiffness of this structure which includes bending, transverse shear, and so forth depends strongly on the geometry of the cell shape, there have been constant improvements in the manufacturing process to optimize cell geometry as well as connecting method. The purpose of this research is to discuss the comparison of structural behavior of this new sandwich structure Pyramidal Truss Core Panel and conventional honeycomb core sandwich structure panel.

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In this paper, the crash characteristics about truss core panel which used as car floor is discussed. Three different truss core panels is modeled and done dynamic FEM simulation by LS-DYNA software. As the result, we knew that the direction of core arrangement influents energy absorption greatly. The middle member also plays an important role in absorbing energy. However, the react force is almost the same in different cases.

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In this paper, a segmentation algorithm on triangular boundary mesh is proposed based on sharp edge and region growing to extract algebraic element including plane, cylinder, cone, surface of extrusion, ruled surface, surface of revolution, sphere, and fillet. Normal vector and principle curvature of smoothed triangle mesh are calculated firstly, and then sharp edge and strip with large curvature can provide a fundamental partition, allowing an accurate identification of patch types, based on least-square fitting and statistical error distribution. The outstanding merit of proposed method lies on the accurate boundary identification in two orders by sharp edge and sharp strips independently, which result in convenient feature extraction and rather smooth subset boundary. Some complex scanned models are processed on a common PC with 2.7GHZ CPU and 1G memory, with acceptable running time and satisfactory result demonstrating the implementation and reliability of proposed method.

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Creating freeform surfaces is a challenging task even with advanced geometric modeling systems. Generally, reconstructing a surface of arbitrary topological type needs define the surface as a network of spline patches. For the patch junction, the control-mesh of a standard B-Spline surface needs to be locally equivalent to a regular grid. To overcome this limitation, we present a method of automatic reconstruction of T-Spline surfaces of arbitrary topological type. T-Spline control grids permit T-junctions, so lines of control points need not traverse the entire control grid. T-Splines support the merging of several B-Spline surfaces that have different knot vectors into a single gap-free model.

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In this paper, we present an improved semi-automatic model based algorithm for texture replacement of architecture in single image. Compared with previous proposed texture replacement algorithm, the improved one not only enhances replacement accuracy but also reduces amount of user interaction by exploiting relevance between segmented regions. The proposed texture replacement algorithm could help users to picture of architectures with different textures before you paint it as imagine architecture with different textures that you like is a really difficult task. The algorithm proposed is key part of an architecture image processing system developed by us.

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This paper describes an effective segmentation method used in image process system based on mobile devices. As we know, mobile devices are devoid of calculation resources such as memory and storage space. However, segmentation algorithm is very complex and needs significant amount of calculation resources. Our method provides a solution to balance the above aspects based on line-based flood fill algorithm and Gaussian image pre-process methods. In the end of this paper, we provide an example to certificate the validity of our method and compare the results with other methods that have being widely used.

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An automatic mesh generation method using a generalized mapped and frontal method combined for a general solid structure is given. The geometry of a 3D structure is created from solid and shell parts assembled. For solid or shell parts, mapped or frontal method is applied depending on the geometry to generate solid and shell elements. Some applications are demonstrated.

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The parallel computation is a wildly used technology in many researches. As a system project, the Computer Supported Collaborative Work (CSCW) system also can adopts parallel computation to accelerate the system's performance and device usage. The Web cluster is chosen to realize the parallel computation which is the easiest and most available method to construct the parallel system. In order to improve the system's performance, a new scheduling algorithm named ASAS is involved: meanwhile the GPU is also used as another co-processor based on CUDA. Through the evaluation, we conclude that the web cluster binding CUDA is suitable and efficient in CSCW system.

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In this paper, to use basis vector method to change shape of truss core panel for shape optimization, independently made morphing technique is used. As a result, 15.75% of improvement for weight decrease which has same displacement for bending stress compared with cup-shaped panel.

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Recently, obtaining actual human heart shape as voxel data is easy via medical images. Our final goal is the realistic blood flow simulation of an actual heart using the voxel data to assist the diagnosis and treatment in daily medical scene. The heart shape is influenced by the cell behavior at each time, because blood flow is driven by heart contraction and the contraction occurred by cardiomyocyte cell behavior. Therefore considering the fluid-structure interaction driven the cardiomyocyte behavior that is cause of heart wall moving is necessary. Although structure analysis is usually performed based on the Lagrangian frame, we study the fluid-structure interaction simulation based on the Eulerian frame. In this simulation. both behavior flow and structure are analyzed by same way based on the same equation in the Eulerian grid. And the force computed by the cardiomyocyte model "Kyoto Model" drives the heart wall contraction. This interaction simulation system simulated a driving blood flow by cardiomyocyte contraction model.

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