http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
장동환(D. H. Jang),함경춘(K. C. Ham),고병두(B. D. Ko) 한국소성·가공학회 2008 소성가공 : 한국소성가공학회지 Vol.17 No.6
In this paper, the serrated forming process is analyzed with finite element method. The seal should secure the overlapping portions of ligature, which has teeth for ligature to prevent from slipping each other after clamping. In the simulation, rigidplastic finite element model has been applied to the serration forming process. Serration or teeth forming characteristics has been analyzed numerically in terms of teeth geometry based on different forming conditions. Analyses are focused to find the influence of different die movements and geometries on the tooth geometry, which is crucial for securing overlapping portions of ligature. Two major process variables are selected, which are the face angle and entry angle of punch, respectively. Extensive investigation has been performed to reveal the influences of different entry and face angles on the geometry of teeth formation in the simulation. Three different face angles of punch have been selected to apply to each simulation of serrated sheet forming process with every case of punch entry angles. Furthermore, tooth geometries predicted from simulation have been applied to the indention process for comparing proper tooth geometries to secure the sealing.
김상철,함경춘,오범석 韓國非破壞檢査學會 1987 한국비파괴검사학회지 Vol.7 No.1
In this experimental research, fracture mechanisms of spheroidal graphite cast iron(As Cast,annealed and normalized)were investigated by using Acoustic Emission (AE) technique. In this study, the data (AE signal) are digitized and processed with the 8 bits micro-computer (APPLE Ⅱ) connected to the AE measuring device without data processing unit. The source of AE signal was estimated by fractography analysis. The results obtained in this experimental study are summarized as follows: For the heterogeneous materials (spheroidal graphite cast iron) with inclusions which may be considered as cracks, it is found that both low and high AE amplitude appear simultaneously and the load is found to be fluctuated in the final stage of deformation. But the lad is not fluctuated in tension test with low AE amplitude only. AE is measured within elastic region and it is confirmed that 0.2% offset yield load agrees approximately with the load point where AE counts decrease steeply after the point of maximum AE counts.
초음파법을 이용한 탄소성 파괴인성치 평가에 있어서 시험편 크기의 영향
강동명,함경춘,우창기 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4
Elastic-plastic fracture toughness(J_(IC)) by ultrasonic method is evaluated in terms of width and thickness. Widths of specimen in 6061-T6 aluminum alloy are 50㎜ and 100㎜, thicknesses of those are 20㎜ and 25㎜, respectively. Elastic-plastic fracture toughness by ultrasonic method is independent of specimen thickness and side groove. Angle beam probe which are placed on the end of the compact specimen detect the maximum crack extension effectively. Comparing with elastic-plastic fracture toughness by ultrasonic method and that of unloading compliance method, J_(IC) of ultrasonic method are underestimated to that of unloading compliance method. Elastic-plastic fracture toughness of width 100㎜ specimen are underestimated to that of width 50㎜ specimen about 20%.