SANDWICH PLATES WITH THROUGH-THE-THICKNESS AND FULLY POTTED INSERTS -EVALUATION OF DIFFERENCES IN STRUCTURAL PERFORMANCE

A high-order sandwich plate theory, which includes the transverse flex ibility of the core, is introduced. The theory includes separate descr iptions of the face sheets and the core material, and general specific ation of loading and boundary conditions. The theory has been adapted especially for the analysis of sandwich plates with hard points in the form of inserts, and special attention is focused on the problem of s andwich plates with inserts of the 'through-the-thickness' and 'fully potted' types. The governing equations are formulated as a set of coup led first-order differential equations, which are solved numerically u sing the 'multi segment method' of integration. Numerical results obta ined for sandwich plates with 'through-the-thickness' and 'fully potte d' inserts subjected to out-of-plane loading are presented. Special em phasis is focused on describing the active load transfer mechanisms, a nd it is demonstrated that insert/potting and potting/honeycomb intera ction effects play an important rule in the buildup of local stress co ncentrations. A detailed comparison of the results obtained for 'throu gh-the-thickness' and 'fully potted' inserts is presented, and it is s hown that the mechanical response for the latter insert type generally exhibits much more severe stress concentrations than is the case for the first insert type. The paper is concluded with a discussion of des ign aspects including a few guidelines for design. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.