An efficient partitioned coupling algorithm for fluid-structure interaction problems is proposed in this paper. Partitioned coupling algorithms, which can treat a structural problem and a fluid dynamics one independently, seem suitable for large-scale computation in a parallel environment because they can utilize existing parallel analysis codes. In this paper, an iterative partitioned coupling algorithm with line search strategy is newly proposed to improve robustness, accuracy and efficiency. Performance of the proposed method is compared with that of Aitken extrapolation method.

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A unified algorithm for compressible and incompressible flows is introduced to Moving Particle Semi-implicit (MPS) method. Original MPS method was used for incompressible flows. The present algorithm can be applied both incompressible and compressible flows including shock waves. Using the present method, one-dimensional shock tube and two-dimensional dam break problems are solved.

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Three-dimensional SPH (Smoothed Particle Hydrodynamics) simulations on the droplet motion are conducted. The surface tension is expressed as the gradient of the tensor and formulated as the interaction between SPH particles so that the total momentum should suitably be conserved. The axi-symmetric oscillation of a droplet is calculated as the first step and the vibration frequency corresponds properly to the theoretical value. The binary collision of equal-sized liquid drops is also simulated, and the subsequent coalescence or re-separation is observed for various impact parameters.

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The dendritic solidification is one of the self-organization phenomena caused by two opposite driving forces, inverse-thermal gradient and the surface energy at the solidification. We used phase-field model for the simulation of pure-Ni dendritic solidification in the undercooling liquid with periodic thermal noise. At the vicinity of dendrite tip, local interfacial energy shows the periodical oscillatory distribution, independent from thermal noise, under the paraboloidal coordinates. Some periodic changes of second arms in dendrites were caused from the beats from intrinsic oscillation and thermal noise. These thermal and energy wave could be understood from wave theory of dendrite.

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Elastic wave propagation characteristics through a fiber-reinforced composite layer are studied by the two-dimensional steady-state finite element analysis. To this purpose boundary conditions are formulated which account for the connection of the model domain to the semi-infinite regions as well as certain periodicity of the fiber arrangement. The transmission characteristics through a composite layer are computed for the longitudinal and transverse wave incidence, assuming a finite number of fiber alignments.

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Inelastic deformations of Polyethylene under total strain control in proportional and non-proportional strain paths in a biaxial state of stress were simulated by a viscoplastic constitutive equation proposed by the present authors. The constitutive equation was formulated by combining the kinematic hardening creep theory of Malinin and Khadjinsky with the nonlinear kinematic hardening rule of Armstrong and Frederick. The nonlinear kinematic hardening rule was modified by a loading surface defined in a viscoplastic strain space and a new parameter using the loading surface. The simulation was performed by the total strain control in various strain paths under cyclic conditions, and the response of normal and shear stresses were compared with experimental results of polyethylene. Then the validity of the constitutive equation was discussed.

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