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오주선 ( Oh J. S. ),정우진 ( W. J. Chung ),박성운 ( S. U. Park ),박영준 ( Y. J. Park ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2017 강원 농업생명환경연구 Vol.29 No.3
Drivers of agricultural tractors are exposed to high levels of vibration for a long period of time because of the nature of their work. Thus, they have a high risk of musculoskeletal disorders such as fatigue accumulation, lumbar spine and neck pain. Various studies have been carried out to reduce ride vibration of agricultural tractors; however, because these studies mainly considered the driving. This study was conducted to evaluate ride vibrations experienced by tractor operators during plowing, rotovating, and transporting operations in Korea. Field data of ride vibrations were analyzed based on ISO 2631-1. The test was carried out at the Tongyangmoolsan R&D Center in Gongju, Chungcheongnam-do, at 3-20 km/h on the asphalt road and at 3 km/h on the field. From the analysis of the results, it follows that ride vibration is highest during rotary work. The magnitude of the vibration during rotary work was 1.62 times larger than the vibration during plow work. Additionally, it was confirmed that the magnitude of ride vibration increases as the tractor driving speed increases.
마르텐사이트계 열간단조용 비조질강의 미세조직이 강도 및 인성에 미치는 영향
주웅용,이덕락,박성운 대한금속재료학회(대한금속학회) 1996 대한금속·재료학회지 Vol.34 No.5
The development of microstructures in micro alloyed forging steels was controlled by applying different cooling rate after hat rolling. The water quenching led to the formation of lath and auto-tempered martensite while the air cooling resulted in bainite and M-A constituents. As the cooling rate increased, the size of M-A constituents decreases and the constituents elongated to the specific direction. Since high carbon twinned martensites in the air cooled specimen caused the brittle fracture, the air cooled specimen showed a low toughness.