• 한국전산구조공학회논문집
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• 제16권1호
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• pp.77-86
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• 2003

비행체의 선회운동 시 액체연료 저장탱크의 동응답을 ALE(arbitrary Lagrangian-Eulerian) 유한요소법을 이용하여 해석하였다. 연료탱크는 선회운동 시 내부 연료의 관성력에 의해 상당한 양의 충격하중을 받게 된다. 또한 이로 인해 유발된 큰 동 하중과 모멘트는 구조물의 안정성과 제어시스템에 영향을 미친다. 본 논문에서는 내부연료의 동적 영향력을 억제하기 위하여 링형배플을 채용하였다. 배플개수와 배플위치에 따른 연료탱크의 파라메트릭 해석을 통하여 연료탱크의 동응답 특성에 미치는 배플의 영향을 분석하였다. 유체와 구조물 사이의 연계는 ALE 유한요소법을 통하여 정확하고 효과적으로 처리되었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권3호
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• pp.318-328
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• 2018

Disk type underwater gliders are a new type of underwater gliders and they could glide in various directions by adjusting the internal structures, making a turnaround like conventional gliders unnecessary. This characteristic of disk type underwater gliders makes them have great potential application in virtual mooring. Considering dynamic models of conventional underwater gliders could not adequately satisfy the motion characteristic of disk type underwater gliders, a nonlinear dynamic model for the motion simulation of disk type underwater glider is developed in this paper. In the model, the effect of internal masses movement is taken into consideration and a viscous hydrodynamic calculation method satisfying the motion characteristic of disk type underwater gliders is proposed. Through simulating typical motions of a disk type underwater glider, the feasibility of the dynamic model is validated and the disk type underwater glider shows good maneuverability.

• 한국정밀공학회지
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• 제32권5호
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• pp.415-422
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• 2015

Ballscrews are important motion transfer and positioning units of industrial machinery and precision machines. Positioning accuracy of the feed drive system depends upon axial stiffness of ballscrew systems. As the nut stiffness depends upon preload and operating conditions, analytical modeling of the stiffness is performed through the contact and body deformation analysis. For accurate contact analysis, the contact angle variation between balls and grooves is incorporated in the developed model. To verify the developed mathematical stiffness model, experiments are conducted on the test-rig. Through the uncertainty analysis according to GUM (Guide to the expression of Uncertainty in Measurement), it is confirmed that the formulated stiffness model has over 85% estimation accuracy. After constructing the ballscrew DB, a quick turnaround system for the nut stiffness estimation has been developed in this research.