Analysis and tests of reinforced carbon-epoxy/foam-core sandwich panels with cutouts

You are here: Homepage > Search

Analysis and tests of reinforced carbon-epoxy/foam-core sandwich panels with cutouts

Baker, D.J. / Rogers, C.

A structurally-efficient minimum-gage shear-panel design concept has been developed that can be used for light helicopters. The shear panels are based on an integrally stiffened syntactic-foam stabilized-skin concept with an all-bias-ply tape construction for the skins. This sandwich concept is an economical way to increase the bending stiffness of the panel with a minimum weight penalty. The concept of using unidirectional carbon-epoxy tape on a syntactic-foam co-cured with the skin as a stiffener is an effective concept for improving the buckling strength. The use of pultruded carbon-epoxy rods embedded in a syntactic-foam and overwrapped with a bias-ply carbon-epoxy tape to form a reinforcing beam is a effective method for redistributing load around a rectangular cutout. The buckling strength of the reinforced panels are 83 to 90 percent of the predicted strength from linear analysis. The failure strength of the reinforced panels was 250 to 400 percent of the buckling strength. The experimental deflections exceed the deflections predicted by a nonlinear analysis by approximately one panel thickness. The efficient shear-panel design exceeds the ultimate strength requirement of 300 lbs/in by over 200 percent.