A study on forced vibration behaviors of composite main wing structure of the 20 seat class small scale WIG craft

In this study, the structural design and forced vibration analysis were performed about the composite main wing structure exited by a pusher type two-stroke reciprocating engine for the WIG (Wing-in-Ground Effect) craft. It was assumed that excitations for the frequency response analysis are the horizontal mode, the vertical mode and the twisted mode which are typical engine vibration modes, and excitation for the transient response analysis is the longitudinal mode with the oscillating propeller thrust. According to the forced vibration analysis results, it was found that the wing skin under the engine mount was unstable. In order to solve this problem, the anti-symmetric design method is used in the wing structure. And also, the stiffener ribs beside the engine mount and the rubber pad were finally added. After design modification, the structural analysis, the normal mode analysis, the frequency response analysis and the transient response analysis were performed again for confirming structure safety and vibration behaviors. The modified structural design feature could alleviate effectively the vibration amplitude.