Structural Optimization of a Co-Axial Compound Rotorcraft by using Three-Dimensional Finite Element Representation

A three-dimensional detailed design procedure is proposed for the internal layout optimization of a co-axial compound rotorcraft. The present design procedure consists of the following two phases. In its first phase, the detailed three-dimensional configuration is obtained by a robust procedure. This procedure constructs the detailed internal layout based on the structural integrity and aeromechanical stability analysis. Along with such, structural optimization is attempted, and the structural weight will become more precise than that estimated by the trend formula. It is found that the first phase has the capability to predict the component weight accurately. And then, the second phase is performed for estimating the more realistic internal layout. The present procedure accounts the volume of the components and the internal layout will be reconstructed by including the realistic component volume. By applying those phases, the internal layout of the compound rotorcraft will become more realistic.