Similarity Conditions for Sandwich Shell-Like Configurations

Abstract

There is renewed interest in the use of sandwich construction, especially for future large transport aircraft. The design and manufacture of these aircraft will require extensive experimental evaluation, which consists of the verification of the design before going to production. This step, the experimental verification, requires the production and testing of large components and prototypes, which is very expensive and time consuming. Use of similitude theory to establish similarity among structural systems can reduce the time and expense by testing small-scale models and use their data to predict the behavior of large prototypes. This paper deals with the derivation of similarity conditions (scaling laws) for shell-like sandwich configurations. These conditions are needed to (a) design the small-scale models and (b) predict the behavior of the large prototype by employing the test data of the small-scale model and the scaling laws. The basis of the derivation of the scaling laws is that both systems are analytically governed by the same equations. Through the use of scale factors (prototype/model parameters) one can find the conditions under which the two systems of governing equations become identical. Both the symbolic code “MAPLE” and the long hand manipulation of equations were used in the derivation of the similarity conditions. Details of the use of the symbolic code are not given, herein.