Analysis of polyhedral domed sandwich structures

Abstract

The finite element method was employed for the analysis of the polyhedral domed sandwich structures. Two different variational approaches were used for comparison reasons. These are the "displacement formulation" and the "mixed formulation" as they are commonly known. Initially seven sandwich plate bending models were developed. These models were used to solve a number of problems where a numerical or experimental solution existed and comparisons were made. The agreement varied from fair to excellent depending on the nature of the model and the type of the solved problem. As a result of this comparative study four of these models were consequently selected to be extended for the development of the sandwich dome models. The accuracy of these four sandwich dome models was tested by modelling five polyhedral dome structures. The results derived from each individual model were compared with experimental results obtained by other researchers and by the author himself. The author's contribution to the experimental work was the design, construction and subsequent testing of two full scale prototypes, namely, the 24 faced and the 36-faced domes. From the whole analysis it was established that the developed numerical models, when selectively applied in the most appropriate way with regard to their special characteristics and the nature of the problem, produce reliable results. Special problems were investigated arising from the boundary conditions as well as structural details! of the joint-lines. of the plates forming the polyhedron, and thus a solution was suggested. Finally, a data generation routine is also described in order to facilitate further application of the various developed models by future users or researchers.