http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Convergence studies for Enriched Free Mesh Method and its application to fracture mechanics
Matsubara, Hitoshi,Yagawa, Genki Techno-Press 2009 Interaction and multiscale mechanics Vol.2 No.3
The Enriched Free Mesh Method (EFMM) is a patch-wise procedure in which both a displacement field on an element and a stress/strain field on a cluster of elements connected to a node can be defined. On the other hand, the Superconvergent Patch Recovery (SPR) is known to be an efficient post-processing procedure of the finite element method to estimate the error norm at a node. In this paper, we discuss the relationship between solutions of the EFMM and those of the SPR through several convergence studies. In addition, in order to solve the demerit of the smoothing effect on the fracture mechanics fields, we implement a singular stress field to a local patch in the EFMM, and its effectiveness is investigated.
Numerical Calculation of Energy Release Rates by Virtual Crack Closure Technique
Choi, Jae-Boong,Kim, Young-Jin,Yagawa, Genki The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.11
A seamless analysis of material behavior incorporating complex geometry and crack- tip modeling is one of greatly interesting topics in engineering and computational fracture mechanics fields. However, there are still large gaps between the industrial applications and fundamental academic studies due to a time consuming detailed modeling. In order to resolve this problem, a numerical method to calculate an energy release rate by virtual crack closure technique was proposed in this paper. Both free mesh method and finite element method have been utilized and, thereafter, robust local and global elements for various geometries and boundary conditions were generated. A validity of the proposed method has been demonstrated through a series of fracture mechanics analyses without tedious crack-tip meshing.
Numerical Calculation of Energy Release Rates by Virtual Crack Closure Technique
Yoon-Suk Chang,Jae-Boong Choi,Young-Jin Kim,Genki Yagawa 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.11
A seamless analysis of material behavior incorporating complex geometry and crack-tip mo-deling is one of greatly interesting topics in engineering and computational fracture mechanics fields. However, there are still large gaps between the industrial applications and fundamental academic studies due to a time consuming detailed modeling. In order to resolve this problem, a numerical method to calculate an energy release rate by virtual crack closure technique was proposed in this paper. Both free mesh method and finite element method have been utilized and, thereafter, robust local and global elements for various geometries and boundary conditions were generated. A validity of the proposed method has been demonstrated through a series of fracture mechanics analyses without tedious crack-tip meshing.<br/>
Resonant behavior and microfluidic manipulation of silicone cilia due to an added mass effect
Lee, Tae-Rin,Oh, Kieseok,Chung, Jae-Hyun,Chang, Yoon-Suk,Choi, Jae-Boong,Yagawa, Genki,Kim, Young-Jin Royal Society of Chemistry 2011 Soft matter Vol.7 No.9
<P>In a microfluidic device, cilia are good candidates to generate complex flow in solution by stirring the microscale fluid. To realize the potential as a novel microfluidic system, it is essential to understand the resonant behavior of cilia in solution and optimize the performance of a cilia-based device. In this paper, the resonant behavior of polydimethylsiloxane (PDMS) cilia in water is investigated by a novel computational method in order to understand the underlying physics and to suggest the optimal design of a cilia-based device. The resonant frequency of a single cilium in water is quantitatively compared to both analytical solutions and experimental results considering an added mass effect. Also, to propose the optimal design of cilia-based device as a microfluidic mixer, the fluid velocity and the pressure in multiple cilia are analysed according to the spacing between neighboring cilia. When the spacing increases from 100 µm to 600 µm, the flow pattern generated by the tips of cilia is changed from a large vortex to multiple small vortexes, which can be utilized for transport, separation and reaction of biomolecules. The particle dispersion with the mixing efficiency in multiple cilia is analysed to predict the performance as a microfluidic device.</P> <P>Graphic Abstract</P><P>Depending on the spacing between resonating cilia, voltex flows can be either merged or separated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0sm01294g'> </P>
다차원 설계윈도우 탐색법을 이용한 마이크로 액추에이터 형상설계
정민중,김영진,다이수케이시하라,시노부요시무라,겐기야가와,Jeong, Min-Jung,Kim, Yeong-Jin,Daisuke Ishihara,Yoshimura, Shinobu,Yagawa, Genki 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.11
For micro-machines, very few design methodologies based on optimization hale been developed so far. To overcome the difficulties of design optimization of micro-machines, the search method for multi-dimensional design window (DW)s is proposed. The proposed method is defined as areas of satisfactory design solutions in a design parameter space, using both continuous evolutionary algorithms (CEA) and the modified K-means clustering algorithm . To demonstrate practical performance of the proposed method, it was applied to an optimal shape design of micro electrostatic actuator of optical memory. The shape design problem has 5 design parameters and 5 objective functions, and finally shows 4 specific design shapes and design characters based on the proposed DWs.