- 著者
- Hyunho SHIN Hun-Joo LEE Yo-Han YOO Woong LEE
- 出版者
- The Japan Society of Mechanical Engineers
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.47, no.1, pp.35-41, 2004 (Released:2004-07-15)
- 参考文献数
- 16
- 被引用文献数
- 4 10
A determination procedure for element elimination criterion in finite element simulation of high-strain-rate impact and penetration phenomena, occurring between tungsten heavy alloy long-rod penetrators and steel targets, has been presented with some demonstrations for the validity of the established criterion. The element elimination criterion for the two types of materials have been determined by comparing the simulated depth of penetration (DOP) and deformed shape of the penetrator with previously available experimental results. Although the criterion affects the simulated DOP significantly at the studied impact velocity of 1500m/s, once established, they are shown to be valid in predicting the DOP in the impact velocity range between 1100 and 1750m/s. The events of partial penetration with severe material deformation such as critical ricochet angle and ricochet phenomenology have also been successfully predicted using the established criterion in the similar impact velocity range. Thus it is suggested that the determination procedure for the suitable element erosion criterion is prerequisite in simulating high-strain-rate impact/penetration phenomena and the criterion established by the procedure is useful in fairly broad range of the velocity and for other similar high-strain-rate events.
- 著者
- Chi-Kyung KIM
- 出版者
- The Japan Society of Mechanical Engineers
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.46, no.2, pp.103-108, 2003 (Released:2004-06-25)
- 参考文献数
- 11
- 被引用文献数
- 1 1
The time-discontinuous Galerkin method based upon using a finite element formulation in time is derived. This method is to use the weighted residuals to treat space and time in a uniform manner and thus integrating both the spatial and temporal variations of the unknown quantities simultaneously. The approximations are continuous with respect to the space variables for each fixed time, but they admit discontinuities with respect to the time variable at each time step. Interpolation functions and weighting functions are taken to be discontinuous across inter-element boundary. This method generates a complete space-time finite element discretization which eliminates the need for any additional ordinary differential equation solver to resolve the temporal behavior of the problem. No significant instability problems and much more rapid convergence to the analytical solution were experienced in this approach than the semidiscretization method.
- 著者
- Juhachi ODA Jiro SAKAMOTO Kenichi SAKANO
- 出版者
- The Japan Society of Mechanical Engineers
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.49, no.3, pp.390-396, 2006 (Released:2007-01-25)
- 参考文献数
- 6
- 被引用文献数
- 30 44
A woodpecker strikes its beak toward a tree repeatedly. But, the damage of brain or the brain concussion doesn’t occur by this action. Human cannot strike strongly the head without the damage of a brain. Therefore, it is predicted that the brain of a woodpecker is protected from the shock by some methods and that the woodpecker has the original mechanism to absorb a shock. In this study, the endoskeltal structure, especially head part structure of woodpecker is dissected and the impact-proof system is analyzed by FEM and model experiment. From the results, it is obvious that the woodpecker has the original impact-proof system as the unique states of hyoid bone, skull, tissue and brain. Moreover it is considered that woodpecker has the advanced impact-proof system relating with not only the head part but also with the whole body.
- 著者
- Osamu NISHIMURA
- 出版者
- The Japan Society of Mechanical Engineers
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.47, no.4, pp.527-532, 2004 (Released:2005-04-15)
- 参考文献数
- 5
- 被引用文献数
- 2 4
This paper presents the characteristics of Social Common Capital (SCC) and its role in the society of abundance. Also, it is explained why bamboo is regarded as the symbol of SCC. The society of abundance has three main characteristics. First, it should rest on the foundation of Institutionalism. Moreover, sustainable development without destruction of natural and cultural environments is required. Finally, the society of abundance should not only provide material richness, but also bring about the acceptance of ethical norms and affection toward natural and cultural environments. SCC is the social equipment sustaining the society of abundance. It can be said that bamboo might serve as an excellent example to exemplify how our society might attain sustainability and affluence, because bamboo is widely used for various ends such as the production of furniture or construction materials. Furthermore, bamboo is also important in relation to the formation of Japanese arts and literature.
- 著者
- Taketoshi NOJIMA Kazuya SAITO
- 出版者
- 社団法人 日本機械学会
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.49, no.1, pp.38-42, 2006 (Released:2006-07-15)
- 参考文献数
- 6
- 被引用文献数
- 12 65 22
By folding a thin flat sheet with periodically set slits or punched out portions into the third dimension, ultra-lightweight strong and functional core models are newly devised. The basic idea of this modeling arises from the application of origami technique to engineering. Based on the space filling models, fundamental flat cores and skew type sponge cores have been newly developed. By applying these models, such modified core models as curved cores and 3D honeycomb core are newly devised.
- 著者
- Hayashi Terutake Maekawa Katsuhiro Tamura Masashi HANYU Kenichi
- 出版者
- 一般社団法人日本機械学会
- 雑誌
- JSME International Journal Series A Solid Mechanics and Material Engineering (ISSN:13447912)
- 巻号頁・発行日
- vol.48, no.4, pp.369-375, 2005-10-15
- 被引用文献数
- 25
The present paper investigates the laser sintering of titanium sheets toward the fabrication of porous artificial bones. The novelty lies in the use of a titanium powder sheet mixed with an organic binder and the application of selective laser sintering to the fabrication of a laminated porous structure. Alternating irradiation of Nd: YAG pulses with short scanning paths results in the suppression of distortion of the sintered part as well as enhanced mechanical properties. Under the appropriate conditions identified in the experiment, a bending strength of 63MPa and a Young's modulus or 1.5GPa are attained when the load is applied parallel to the lamination direction, whereas load vertical to the lamination direction yields 79MPa and 1.8GPa, respectively. The size of pores varies from 200 to 300μm, and the porosity is approximately 65%. These values, other than Young's modulus, are almost equivalent to those of human bones.