DYNAMIC RESPONSE OF CURVED COMPOSITE PANELS IN A THERMAL ENVIRONMENT,.
NORTHROP CORP HAWTHORNE CALIF NORAIR DIV
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In order to obtain a simplified vibration theory for curved sandwich plates in a thermal environment, differential equations are derived from a small deflection Donnell-type theory for the displacements of shallow cylindrically curved sandwich panels, e.g., honeycomb panels, with thin isotropic facings. It is assumed that normals to the undeformed middle surface remain straight lines but not necessarily normal to the deformed middle surface and that the transverse deflection does not vary through the thickness. The facings may be of different thicknesses and at different temperature levels. The plates may be subjected to a spatially uniform lateral pressure and in-plane loads. The lateral loading may be either harmonic or random in time. It is assumed that the bending is taken only by the facings and the transverse shear stresses only by the core, which may be orthotropic. Viscous damping is assumed. The differential equations are solved for the case of simply supported boundary conditions. A computer program was developed for the free and forced vibration cases for honeycomb panels. In free vibration, natural frequencies and model shapes are predicted. In harmonic and in random forced vibrations, the deflections and stresses resulting from the flexure caused by the dynamic lateral loading in the presence of static in-plane loads are predicted. For extremely large radii, the results from the computer program are applicable to flat sandwich plates. Author
- Structural Engineering and Building Technology