Chen D.H.,Tokyo University of Science |
Ushijima K.,Kyushu Sangyo University
Thin-Walled Structures | Year: 2011
This paper discusses the estimation of the initial peak load for circular tubes subjected to axial impact based on a finite element analysis. The peak load depends on the material properties, tube geometries and impact velocity. By changing some parameters systematically, effects of material properties and tube geometries on the peak load are explored. Also, the effect of the impact velocity on the peak load implies both the inertia effect and the material strain rate dependency. By observing the axial stress distribution and deformation behaviour in detail, and by calculating the strain rate near the vertex of a wrinkle when the peak load is observed, both effects on the peak load are clarified. Moreover, an approximate equation to evaluate the peak stress is proposed and in good agreement with the FEM results and other researcher's results under a relatively low impact velocity ( V0<40m/s). © 2011 Elsevier Ltd.
Ushijima K.,Kyushu Sangyo University |
Cantwell W.J.,Khalifa University |
Chen D.H.,Tokyo University of Science
International Journal of Mechanical Sciences | Year: 2013
The mechanical properties of micro-lattice structures subjected to a normal stress state are investigated using both a classical beam theory approach and the finite element technique. In particular, an approach for predicting the yield surface of lattice structures subjected to either a uniaxial or a biaxial stress state is proposed. In addition, the geometrical and material conditions for the occurrence of elastic buckling under a triaxial stress state are identified. The stiffness and plastic collapse strengths of the micro-lattice structures are compared with the corresponding properties of other lightweight structures. It is shown that micro-lattices offer significant potential for use in the design of lightweight cellular structures. © 2013 Elsevier Ltd.
Kaneko K.,Kyushu Sangyo University |
Sun Y.,Shanghai JiaoTong University |
Sun Y.,CAS Lanzhou Institute of Modern Physics |
Mizusaki T.,Senshu University |
Tazaki S.,Fukuoka University
Physical Review Letters | Year: 2013
For mirror nuclei with masses A=42-95, the effects of isospin-nonconserving nuclear forces are studied with the nuclear shell model using the Coulomb displacement energy and triplet displacement energy as probes. It is shown that the characteristic behavior of the displacement energies can be well reproduced if the isovector and isotensor nuclear interactions with J=0 and T=1 are introduced into the f7/2 shell. These forces, with their strengths being found consistent with the nucleon-nucleon scattering data, tend to modify nuclear binding energies near the N=Z line. At present, no evidence is found that these forces are needed for the upper fp shell. Theoretical one- and two-proton separation energies are predicted accordingly, and locations of the proton drip line are thereby suggested. © 2013 American Physical Society.
Akasaka R.,Kyushu Sangyo University
International Journal of Thermophysics | Year: 2011
New fundamental equations of state explicit in the Helmholtz energy with a common functional form are presented for 2,3,3,3-tetrafluoropropene (R-1234yf) and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)). The independent variables of the equations of state are the temperature and density. The equations of state are based on reliable experimental data for the vapor pressure, density, heat capacities, and speed of sound. The equation for R-1234yf covers temperatures between 240K and 400 K for pressures up to 40MPa with uncertainties of 0.1 % in liquid density, 0.3 % in vapor density, 2 % in liquid heat capacities, 0.05 % in the vapor-phase speed of sound, and 0.1% in vapor pressure. The equation for R-1234ze(E) is valid for temperatures from 240 K to 420 K and for pressures up to 15MPa with uncertainties of 0.1% in liquid density, 0.2 % in vapor density, 3 % in liquid heat capacities, 0.05% in the vapor-phase speed of sound, and 0.1% in vapor pressure. Both equations exhibit reasonable behavior in extrapolated regions outside the range of the experimental data. © Springer Science+Business Media, LLC 2011.
Yonemoto S.,Kyushu Sangyo University
Proceedings of the International Conference on Information Visualisation | Year: 2013
In this paper, we present a marker-less AR framework which enables virtual graffiti creation and reference image generation. Our framework also supports 3D annotations such as image textures (virtual graffiti), 3D objects and 3D text, which are superposed over the video stream. We adopt marker-less tracking technique based on key point based descriptors and the trackers. In general, reference image for marker-less AR must be acquired from real image in advance. In such situation, most marker-less tracking approaches force user to capture the front view of a target object. We suppose that reference image does not have to be captured under such condition. In experiments, we showed the estimation accuracy for reference image generation. And we demonstrated real-time marker-less tracking including reference image generation, easy-to-use virtual graffiti creation and immediate superimposing. © 2013 IEEE.