Carbon fiber reinforced plastic composites (CFRP) exhibit complex failure mechanisms because they include fiber–matrix and interlaminar interfaces. Detailed modeling of fibers, matrices, and interfaces for conducting accurate progressive damage analysis requires large-scale finite element models. We developed parallel finite element analysis software, that can simulate failure of large-scale CFRP models including interfaces using cohesive elements. We verified the software comparing with proven commercial software. In addition, we validated the software using double cantilever beam tests. The simulation result agrees well with the experimental one. The software can analyze progressive interface damage of large-scale models with more than 77 million degrees of freedom.

Using magnetic field to confine the plasma can realize controlled nuclear fusion. A device called Force Free Helical Reactor (FFHR) using helical coils to generate a magnetic trap is being designed by National Institute for Fusion Science (NIFS) in Japan. Because the FFHR has the plasma with a complicated three-dimensional (3D) structure, 3D de-sign of the in-vessel components is necessary. In the past, the design of the in-vessel components has been conducted based on the discrete two-dimensional poloidal cross-sectional shapes. However, this method is not effective and complete check of the interference is difficult. Since plasma movement follows the magnetic field lines, the plasma shape could be generated from them. Marching cubes method is applied for generating the polygon mesh. A graphic software is used for modifying and rendering.

In this paper, we develop a visualization toolkit called YYZVis, which can efficiently handle a new overset grid in a sphere composed of Yin, Yang, and Zhong grids. Conventionally, in order to visualize the overset grid dataset, it must be merged into a single uniform structured volume. However, this merging process may increase memory and time complexities, and some artifacts may occur owing to interpolation errors around the boundaries of the sphere. In YYZVis, the Yin-Yang-Zhong (YYZ) grid dataset can be visualized without any grid merging process. YYZVis provides basic visualization functionalities such as isosurfaces, slice planes, and volume rendering, as modules comprise the visualization pipeline. Therefore, YYZVis allows us to efficiently develop a visualization system by combining our proposed modules with existing modules. In the experiments, we applied YYZVis to a magnetohydrodynamics simulation result and confirmed its effectiveness.

In this paper, we calculated the radiation from the state where an electron in cyclotron motion under the uniform magnetic field B_ex was accelerated by the externally applied circularly polarized wave with strong E_in and B_in. The electron was accelerated in the parallel direction by the term β_⊥ × B_in (β_⊥: perpendicular velocity of the electron) as well as in the perpendicular direction by the electric field of the wave E_in. Then, the electron can be resonantly accelerated when the B_ex is set to the magnetic field strength which is equivalent to frequency of the externally applied circularly polarized wave. The radiation from such an accelerated electron was confirmed to have helical wavefront at harmonics cyclotron frequency.

The present paper shows a new approach for solving two types of fluid problems, which has recently emerged and has been an unsolved mysteriously for over 100 years. The first problem emerged recently is a very small amount of numerical errors comparable to pollutant emissions such as unburned hydrocarbon fuel (HC) and NOx at order of ppm or less. A new nonlinear numerical method of global and local corrections for the deterministic compressible Navier-Stokes equation for multi-components of gases is proposed and tested to overcome this first problem, while accurately evaluating fluid-dynamic instability related to turbulence and thermal efficiency as result of spatially-integrated thermodynamic quantities, related to total amount of CO2 exhausted, in power systems including combustion engines. It is stressed that the present nonlinear correction method applied for the stochastic Navier-Stokes equation is also effective for the second mysterious problem which has been unsolved for over 100 years, which is the spatial transition point from laminar to turbulent flows in pipes.

A method is proposed for estimating the original radiation source distribution by machine learning using the dose and energy spectrum of γ rays emitted from radiation sources placed at various positions. This method does not require complicated parameter settings and can be also applied when there is a shield liked Pb between the radiation source and the measurement point. The estimation results displayed the original radiation source distribution with high accuracy. It is expected to be used for decontamination and decommissioning by developing this method.

To improve the performance of organic photovoltaics, we investigate an integrated device design in which the hybrid antireflection structure, composed of a surface moth-eye nanotexture and a multilayer interference film, is applied with a high-refractive-index glass substrate. The moth eye texture with a relatively long period, which is near the bandgap wavelength of organic semiconductors, is used to enhance light absorption. We perform the optical finite-difference time-domain simulation for the integrated device and find the optimal layer configuration of the multilayer interference film to maximize the photocurrent generation. In addition, we compare the absorption spectrum of the integrated device and that of the device with only moth eye coating, and show that the integrated structure is beneficial to realize a high level of absorption relatively uniformly as function of wavelength.

To construct an open cell metal foam model, a simple method using spheres has been proposed. In this method, spheres are arranged so that the edges are constructed as Plateau borders, and an implicit surface f (x) = 0 combined by constructive solid geometry is generated from these spheres. The open cell metal foam model generated by the proposed method has edges and junctions, and the cross-sections of Plateau borders in the model are concave triangles. In the proposed method, the open cell model that has a periodic structure can be generated by adjusting the arrangement of spheres. In addition, by employing the p-norm-based implicit surfaces, the proposed method has been extended so that various kinds of open cell model can be constructed. Although the open cell models generated by the proposed method are midair models, they can be converted to solid models constructed as voxel meshes. Furthermore, an arbitrary shape defined by an implicit surface g(x) = 0 can be represented as a collection of extracted cells in the voxel mesh of open cell model.

The present paper is an effort to introduce the modeling architecture of analyzing the response of a supply chain of bottled water due to consumer panic buying triggered by a large-scale natural disaster. An agent-based system is used to model a simplistic consumer purchase model and a supply chain model. Disaster prompts panic buying among the consumers, which disturbs the supply chain. The strategies used to control the excess demand such as limiting sales per person is considered to understand the effect on the supply chain. A preliminary study of the response of the supply chain due to the disaster and its consequences are presented in this paper.

Skin modeling is an ongoing research area that highly benefits from modern parallel algorithms. This article aims at applying shape optimization to compute cell size and arrangement for elastic energy minimization of a cellular composite material model for the upper layer of the human skin. A gradient-penalized shape optimization algorithm is employed and tested on the distributed-memory cluster Hazel Hen, HLRS, Germany. The performance of the algorithm is studied in two benchmark tests. First, cell structures are optimized with respect to purely geometric aspects. The model is then extended such that the composite is optimized to withstand applied deformations. In both settings, the algorithm is investigated in terms of weak and strong scalability. The results for the geometric test reflect Kelvin's conjecture that the optimal space-filling design of cells with minimal surface is given by tetrakaidecahedrons. The PDE-constrained test case is chosen in order to demonstrate the influence of the deformation gradient penalization on fine inter-cellular channels in the composite and its influence on the multigrid convergence. A scaling study is presented for up to 12,288 cores and 3 billion DoFs.

This paper describes a numerical verification method for positive solutions of the Allen–Cahn equation on the basis of the sub- and super-solution method. Our application range extends to global-in-time solutions that converge or sufficiently approach to stable stationary solutions. The proposed verification method has almost the same memory requirements as the computation for obtaining an approximate solution.

This paper proposes a low-profile wideband antenna composed of a capacitance disk, trapezoidal plate, and four oblique short elements. The characteristics of the proposed antenna are analyzed through simulation. The results demonstrate that the proposed antenna offers a low-profile and wideband performance. In addition, its radiation patterns are omnidirectional in horizontal plane. This antenna is prototyped, and the validity of the simulation is verified through measurements.

Cambering in the flapping wings of insects plays an important role in the aerodynamic performance of their flight. In a previous study, the authors proposed a wing model using shell finite elements to elucidate the mechanism of cambering. However, the analysis of a strongly coupled fluid–structure system using this model would be quite computationally expensive because of the necessity of robust mesh-moving techniques. Therefore, in this study, a new wing model using rectangular shell finite elements is proposed. In the proposed model, the veins and membranes are described as pseudo-elastic materials. The cambering of the proposed model is investigated by comparison with the previous model.

Although the rigidity of flat honeycomb cores has been previously studied, the rigidity of honeycomb cores with a unique shape has not been extensively investigated. This study aims to determine the rigidity of cylindrical honeycomb cores under static radial loads via linear finite element analysis. Two numerical cylindrical honeycomb models are demonstrated: one satisfies the radial core height alignment condition with distorted core walls; the other cancels the distortion of core walls, but its core height is not completely aligned with the radial direction. The geometrical differences between the models are small. However, our analyses not only reveal clear differences in rigidity but also demonstrate that the differences in rigidity depended on the constraint conditions applied on the models. These results imply that cylindrical honeycomb cores can be applied in the mechanical components that undergo radial loads, such as vehicle tires, robotic rovers, bearings, and liquid containers.

The current distribution in the electromagnet is optimized by using the genetic-algorithm based on-off method so as to maximize the acceleration performance of the Superconducting Linear Acceleration (SLA) system. In the SLA system, a pellet container is accelerated by the interaction between a shielding current density and an applied magnetic field. By using the equivalent-circuit model, the distribution of the shielding current density is approximated as a set of the multiple current loops. In contrast, the current distribution in the electromagnet is represented by means of the on-off method. As the method for optimizing the current distribution in the electromagnet, two types of genetic algorithms are adopted. The results of computations show that the pellet velocity for the optimized current distribution is 1.3 times as fast as that for the homogeneous current distribution.

This paper addresses a fusion visualization of vorticity fields and riverine water maps by combining satellite-derived ocean-color images and simulated velocity fields using a high-resolution ocean model. Our visualization successfully described the transportation of low-salinity riverine water from the Yoshino River through the Naruto Strait. The cloudy white riverine water separated from the river plume in Kii Channel and easily passed through the strait owing to the flood current that formed a mushroom vortex. Meanwhile, the high-salinity clear water from the Harima-Nada Sea could horizontally mix in the strong vorticity fields generated by the ebb current after passing the strait. Our fusion visualization is capable of evaluating the transportation and mixing of riverine water through narrow straits.