Prediction of Dynamic Parameters of Variable Diameter Shell Composite Structure via 2-D Subscale Modeling

Abstract

Prediction of possible vibration responses for a composite structure via subscale modeling is discussed in this article. The analytical correlations for three-dimensional (3-D) subscale modeling for metallic structures cannot be directly used for composite structures. In such structures, change in thickness can alter the mechanical properties of a composite structure and its prototype; therefore, vibration characteristics can only be predicted via two-dimensional (2-D) subscale modeling. For this purpose, the 3-D analytical relations are customized for 2-D subscale modeling along with an additional parameter, i.e., rigidity factor (RF), avoiding violation of dimensional consistency of the structure. They are also validated experimentally for variable diameter glass fiber shell composite structure. Three different approaches were used to develop these empirical correlations, which were then compared to determine the best one, closely matching the experimental results. It is found that empirical relations obtained for the 2-D subscaling technique produces better results against their counterpart 3-D subscale correlations. The dynamic behavior of shell structure can be predicted within a 10 % error band. Moreover, it was found that the research can be applied to all the composite shell structures that are difficult to scale in the third dimension.