Structural finite-element modeling strategies for conformal load-bearing antenna structure (CLAS) (Air Force contract F33615-C-93-3200)

As the Wright Lab Air Force military contrast `Smart Skin Structures Technology Demonstration' (S3TD) Contract No. F33615-C-93-3200 draws toward conclusion, pertinent features of the program finite element modeling are presented. Analysis was performed to predict the structural performance of a complex multilayered composite panel that will be tested structurally (and electrically) for the final program deliverable. Application of finite element modeling to predict component load path and strain distribution in sandwich panel construction has been reported elsewhere in the literature for more standard applications. However, the unauthordox sandwich configuration lay-up posed by the quite revolutionary S3TD CLAS aircraft fuselage panel demonstration article merits further discussion. Difficulties with material selection, the stumbling block for many programs, are further exacerbated by conflicting material properties required to support simultaneous electrical and structural performance roles. The structural analysis challenge derives from S3TD's unique program goal, namely, to investigate load bearing antennas structural configurations, rather than conventional structurally inefficient `bolt in' installations, that have been the modus operandi for tactical aircraft antenna installations to date. Discussed below is a cost saving strategy where use of linear finite element analysis has been employed in the prediction of key structural parameters, and validated with risk reduction sub panel measurements, before proceeding to the final fabrication of a full scale 36 by 36 inch CLAS panel demonstration article.