Determination of the fundamental frequency of a sandwich panel as constructional part of spacecraft body

Sandwich panels are widely used constructional parts of modern spacecraft bodies and have various edge-fixing conditions. In designing of such panels there is always a need for an analytical formula to determine with reasonable accuracy the fundamental frequency which is a convenient assessment of sandwich construction efficiency that takes into account the mutual influence of its stiffness and mass. The article observes fundamental frequency determination for rectangular sandwich panel with all edges rigidly clamped. The panel has symmetrical layer package, consists of two identical face-sheets and orthotropic core. The approach uses Galerkin’s method to solve motion equations and the solution of a bending problem of the beam with rigidly clamped edges as a function that approximate panel shape. This reduces the problem of determination of the dimensionless frequency parameter which depends on the panel geometry, inertial and elastic characteristics. The frequency parameter is calculated both including and excluding rotation inertia. In the latter case, an analytical formula for fundamental frequency is the result of this approach. Influence of geometrical, elastic and inertial parameters of the sandwich panel to its fundamental frequency have been analyzed by using the analytical formula. Comparison of calculation data with finite-element package modal solution shows that obtained formula gives high accuracy and low usage of computational resources, which is especially useful in designing process where restrictions are imposed on the first frequency of sandwich panels.