Abstract: An approximate analysis of wing/store subharmonic flutter response is discussed.The store separated from the wing is treated as piecewise linear oscillator with clearance under harmonic excitation. The symmetric periodic response and bifurcation of such an oscillator is studied.The bifurcation is analysed by Poincare map method and a bifurcation condition is ob-ained. By using equivalent linearization method, and approximate bifurcation equation is derived and is applied to predict the subharmonic response of awign/store flutter system, Feasi-bility of the approximate analysis procedure is confirmed by illustrative example.

Key words: nonlinearity, flutter, piecewise linear oscillator, bifurcation