Stability of ring-stiffened three-layer shell in supersonic gas flow | Mekhanika | kompozitsionnykh | materialov i konstruktsii

Stability of ring-stiffened three-layer shell in supersonic gas flow

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To protect electronic devices and pyrotechnics of flight vehicles from the effects of adverse external factors, sandwich shell structures are used, whose core, having special functional properties, allows for minimum thermal conductivity, radio transparency and acoustic insulation, and the geometrical and physical parameters of the carrier layers make it possible to minimize the structural mass. In this paper we consider the panel flutter of a cylindrical shell, consisting of unsymmetrical orthotropic carrier layers and an orthotropic lightweight core, under an external supersonic gas flow. The shell is discretely stiffened by rings rigidly connected to the carrier layer. Consideration of the tangential component of the contact interaction between the rings and the layers significantly improves the analysis accuracy. The shell edges are hinged and uniformly loaded with compressive forces. The solution is searched in the form of trigonometric series in the longitudinal coordinate using the Bubnov-Galerkin method. The resulting system of algebraic equations is reduced to an eight-degree characteristic polynomial by the Danilevsky method. By implementing the stability parabola equation and lowering the order using algebraic operations, the characteristic equation is reduced to a system of two algebraic equations. The stability of the resulting coefficient matrix is analyzed using the Routh-Hurwitz criterion. The effect of the size, location and number of rings, shell length and compressive force magnitude on the critical flow speed is illustrated with a numerical example.