Data Analysis of Bag/Cushion Heave Forces and Pitch Moments Acting on a 10-Ton SEV While Crossing Isolated Obstacles
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD PROPULSION AND AUXILIARY SYSTEMS DEPT
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A method for evaluating the magnitude of the bag effects on the vehicle dynamics of a surface effect vehicle has been developed. The method involves the calculation of bag heave forces and pitch moments from vehicle acceleration and cushion pressure data. The method is applied to an SK-5 crossing discrete obstacles having obstacle height to cushion height ratios of 0.5 and 1.0. For the cases examined, bag effects as compared to cushion effects are important in heave but not in pitch. Average bag heave forces on the order of 10 and 25 of vehicle weight are typical for the 0.5 and 1.0 obstacles, respectively. A detailed physical description of the cushionobstacle interaction has resulted from the data analysis. Three major data trends - impact, venting, and slamming - are identified and related to cushion geometry. Bag effects have been correlated in terms of obstacle size, vehicle speed, and cushion geometry for ease of application as correction factors for analytical vehicle dynamics models based on cushion pressures only.
- Surface Effect Vehicles and Amphibious Vehicles