[in Japanese]

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With reference to the Sea deep water jack-up off shore platform, designs an experimental model of offshore platforms. Modal experimental system is developed! the vibration mode experiment of similar model is done. TMD design of tuned mass damper (TMD) for damped linear structures has attracted considerable attention in recent years. Some approximate expressions of optimal tuning ratio of a TMD attached to a damped linear structure have been proposed tuned mass damper (TMD) has been extensively used in vibration control of engineering structures. Experiment results show that TMD can greatly reduce the response of elastic structures under wind, water waves, and earthquakes. Vibration experiment of a offshore plant modeled as a single-degree-of-freedom (SDOF) system subjected to the 1940 HACHI-NS earthquake vibration. It is demonstrated that TMD can reduce the peak displacement effectively. The current study also shows that the TMD performs well in a low-intensity earthquake, inwhich the TMD is inactivated due to friction.

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Truss Core Panel is an ultra-lightweight and high-rigidity composite panel. This panel is an origami structure composed of triangular cones, and is used in automotive, aviation and has broad application prospects. Since the constituent elements of the triangular cone densely arranged on a plate, and by forming height restrictions in the process of press forming wrinkles and cracking easily occurs. For this problem, we made use of finite element simulation technology, proposed an Improved Multi-stage Press Forming method, and simulate the process of press forming. By the simulation we found that this method can effectively improve the forming height, and the forming quality can be ensured.

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In recent years, influenced by the earth's environment and energy problems,honeycomb structure of lightweight structure in the automotive, aircraft, machines, and other fields has been widely used. However, because of too pursuit of lightweight, part of the structure are prone to rupture, makes the structure of whole rigid abate, deformation increase. The mechanical structure of the vibration noise becomes more intense, structure quality will appear all sorts of problems. Want to solve this problem, so a lot of light in the field of tough high require material. Lightweight way among them, the machinery industry strength and toughness, vibration and energy absorption characteristics of the conflict is very good, and reduce the cost, also truss core panel development concern. The new truss core panel has been developed using a composite material of glass fiber reinforce plastics (GFRP) to improves the of strength material. In this research, truss core panel of GFRP is produced, and the strength of product is discussed.

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[in Japanese]

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An iterative domain decomposition method is proposed for numerical analysis of 3-Dimensional (3D) linear magnetostatic problems taking the magnetic vector potential as an unknown function. The iterative domain decomposition method is combined with the Preconditioned Conjugate Gradient (PCG) procedure and the Hierarchical Domain Decomposition Method (HDDM). Our previously employed preconditioner was the Neumann-Neumann preconditioner. Numerical results showed that the method was only effective for smaller problems. In this paper, we consider its improvement with a balancing domain decomposition preconditioner (BDD-DIAG).

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[in Japanese]

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Inertia friction welding is a solid state welding process with the small heat affected zone and the high joint quality and therefore expected to be a key manufacturing technology for the jet engine parts. However, development of welding process requires significant effort because it is a complicated thermo-mechanical phenomenon including the high speed friction and the large deformation at elevated temperature and difficult to understand. Simulation is expected as an effective tool in order to reduce long time and high cost experiments to find the process parameters. In this work, the simulation technology for inertia friction welding was developed by means of re-meshing techniques to avoid element distortion. A comparison with analytical result and experimental result was reported.

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[in Japanese]

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In addition to the conventional static elasticity analysis, ADVENTURE_Solid 2.0 expanded the functions such as the dynamic elasticity analysis, the non-linear analysis etc. This paper shows the parallel performance of ADVENTURE_Solid 2.0 on the K computer. In the future performance tuning for the K computer will be done based on these data.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Direct numerical simulation is employed to investigate the turbulent flow characteristics and their effect on local flames for mean reaction rate modelling of turbulent swirling premixed flames. Two swirl number conditions having significant effects on the formation of a central recirculation zone in the combustor are considered. The mean turbulent and heat release rate fields suggest that the heat and radicals from the hot products trapped in the recirculation zones are mixed with the reactants, not only through scalar dissipation rate (i.e.scalar gradient) but also by small-scale processes of turbulence relevant to turbulent kinetic energy dissipation rate. Therefore, both scalar and velocity gradients have a strong influence on the chemical reactions through mixing of cold reactant and hot products. A conventional flamelet and non-flamelet models are used to estimate the mean reaction rate, and to study the balance between these two mixing mechanisms. Although both models show a qualitative agreement with the DNS results, these models compensate their limitations each other, depending on the local turbulence and thermochemical conditions. A simple approach is proposed to exploit the advantages of these two models by considering the balance of two mixing mechanisms based on the chemical and turbulence time scales.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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In this report, we report an example of application based upon non-parametric shape optimization considering the effect of contact. Generally speaking, in this kind of optimization problem, The weight is an objective function, and it is difficult to take all constraint conditions of stress, displacement, and element quality into account. Our goal is to keep a mixed constraint conditions and get a minimum weight and optimized shape for short run time by PERMAS.

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It is important that the assembled parts is tightened with connection like bolts works correctly in order to keep a homogeneous contact pressure on the boundary surfaces. In this report, we investigate not only the static characteristic inspection of the assembled model, but also the dynamics characteristic compared to frequency response function for high accuracy simulation in the contact interface of assembled parts. The dynamics property of the interface element is given for a function depends upon the contact pressure from a result provided by contact analysis. Here, the unique approach of accuracy improvement of FRAC (frequency response assurance criteria) is shown as an example with the assembled parts of brakes.

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[in Japanese]

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A numerical prediction method on the thermal-hydraulic dynamics for the fuel assembly in a spent fuel pool when the water level falls has been developed to clarify that of cooling characteristics. This paper describes predicted results of preliminary analyses based on the two-fluid model combined with oxidation reaction models for the zirconium reaction with water in the spent fuel pool when the water level falls.

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[in Japanese]

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Fatigue strength evaluation for small crack structures using fracture mechanics has a disadvantage as the value of threshold stress intensity factor range must be modified. Many modification models are presented by many researchers, in these modification equations the dominant parameters is crack length. But in actual engineering fields the determination of these small crack length are difficult as the surrounding structures near these small cracks are complicated. In previous papers we introduce critical distance stress theory for fatigue limit estimation of general stress concentrate structures such as circular or elliptical hole, stress singularity structures such as sharp notch, contact edge and adhesive edge structures. All estimated results coincided well with experimental results, and the availability of this method for more wide field structures can be confirmed. In this paper we apply this critical distance stress theory for fatigue strength evaluation of small crack structures. This method need only fatigue limit of smooth specimen σ_<w0>, and threshold stress intensity factor range ΔK_<th> of materials and stress distributions of structures near crack tips. The estimated fatigue limits of small cracked specimens coincided well with experimental results. Finally these estimated and experimental results are compared with other researchers estimated results using equivalent crack length, and the superiority of this critical distance stress theory can be confirmed.

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In case of numerical analysis of Structures with characteristics of anisotropic material, the parameters of physical property must be incorporated with careful consideration. Computing inherent physical property is technically important subjects in performing available numerical analysis as using composite materials of technical products is spreading in recent years. In this study, we take up corrugated boards in anisotropic material and use bending test and numerical analysis by homogenization method for deciding material property and conduct verification and validation on Model Verification and Validation (V&V).

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[in Japanese]

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