Aeroelastic instability of symmetric laminated beam-plates with two delaminations ‎

In this study aeroelastic instability of laminated beam-plates with two overlapping delaminations with equal length that is subjected to supersonic ‎flow is investigated analytically. The classical laminate plate theory with small deflection assumptions with quasi-steady aerodynamic theory is ‎utilized to derive the governing equations of the system. Additionally, it is assumed that the delaminations parts are forced to vibrate with each other. ‎In this case to predict critical flutter pressure, the delaminated composite beam-plates are divided into five parts. The boundary conditions at the ‎ends of beam-plates and at the ends of each delamination region are employed to predict flutter pressure. The effect of different parameters such as ‎delaminations length, axial position, their position through thickness of delaminated beam-plate and different stacking sequence are considered on ‎flutter pressure of beam-plate with two overlapping delaminations. According to the results, flutter pressure of delaminated beam-plate with two ‎overlapping, equal length delaminations in comparison to beam-plate with single delamination is reduced 20 through 40 percentages approximately. ‎Additionally, it has been shown, as far as two delaminations are closer to the mid-plane of the beam-plate, the aeroelastic behavior will change ‎further. ‎