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김현준,이태영,권영휴,Kim, H.J.,Lee, T.Y.,Kwon, Y.H. 국립한국농수산대학교 교육개발센터 2011 현장농업연구지 = Journal of practical agricultural resear Vol.13 No.1
The purpose of this study carried out to analyze production status, pricing trend and distribution status of landscape plants, so that it could predict the demand of landscape plants for the balance of supply and demand. The production amount of landscape plants made constantly increased. The annual output of shrubs increased more higher than that of trees. The prices of trees have raised consistently, but shrubs were susceptible to price fluctuations. And there were still many problems in the distribution structure. The landscaping work has focused on the metropolitan area. And large-scale nationwide projects were scheduled for coming years, so the demand of landscape plants was expected to expend. However, the lack of increase in production amounts of landscape plants, it is cause to supply problems. So, demand forecast was necessary to control the production of landscape plants.
김현준(H.J. Kim),강종훈(J.H. Kang),강성수(S.S. Kang) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.1
본 연구는 외경부에 단이 존재하는 제품의 링롤링작업을 위한 예비성형체의 설계에 관한 연구이다. 형상링롤링 공정에서 가장 일반적으로 나타나는 결함 중 하나는 미충진이며, 변형량이 적을 경우나 외경부 단의 깊이가 클 경우 발생한다. 이러한 미충진을 방지하기 위해서는 변형량을 증가시키거나 예비성형체를 최종형상에 근접하도록 설계하여야 한다. 결함이 없는 제품을 생산하기 위하여 형상비와 성형비를 이용한 충진한계식을 제안하였다. 충진한계식은 네가지 경우에 대하여 유한요소해석과 시험생산한 결과를 토대로 작성되었다. 실물 크기의 형상링롤링 작업을 수행하고 충진한계식을 이용한 예측과 비교함으로써 제안된 방법의 타당성을 검증하였다. This paper introduces a preform design method for a ring rolling process with an outer step. Underfilling is one of the general defects of the profile ring rolling process. It occurs when the deformation amount is small or step depth of the profiled region is large. To prevent underfilling, increasing the deformation amount or using a preform of size similar to that of the final product are required. Furthermore, the filling limit equation is suggested based on the shape factor and deformation ratio for preventing defects in the products. The filling limit equation has been derived through finite element analyses and production tests for four different cases. For verifying the suggested method, realsized profile rolling tests were performed, and test results were compared with the predictions of the equation