Advanced Composite Turboprops: Modeling, Structural, and Dynamic Analyses

This paper presents a structural and dynamic analysis of a scaled-down wind tunnel model prop-fan blade made from fiber composites. This blade is one of a series of prop-fan blades that have been tested at the Lewis Research Center wind tunnel facilities. The blade is highly swept and twisted and of the spar/shell construction. Due to the complexity of the blade geometry and its high performance, it is subjected to much higher loads and tends to be much less stable than conventional blades. The structural and dynamic analyses of the blade were performed using the NASA-Lewis COBSTRAN computer code. COBSTRAN is designed to generate the mesh and calculate the anisotropic material properties for composite blade analysis. Comparison of analytical and experimental mode shapes and frequencies are shown, verifying the model development and analysis techniques used. The methodologies and programs developed for this analysis are directly applicable to other prop-fan blades.