Composite Rotor Blade Sectional Analysis Software

Structural analysis of helicopter rotor blades is an important and difficult problem. The difficulties stem from the use of composite materials with layer drop-offs, complex cross-sections, and possible twist or curvature of undeformed blades. A three-stage analysis approach has been developed by researchers to handle these difficulties in a way that obviates the need for very detailed and unwieldy finite element models composed of tens of thousands of solid elements. In the first stage, one soles a problem in which the cross-section is represented by two-dimensional finite elements and the outcome is a six-by-six stiffness matrix referenced to traditional beam displacements and rotations. In the second stage, these matrices are assembled and the beam equations are solved. In a third stage, detailed stresses and cross-sectional warping deformations may be recovered. We propose to assemble the latest technology for arbitrary cross-sections as well as curved and twisted shapes into a software package for convenient design/analysis of rotor blades. We will surpass the requirements of the solicittaion by adding a sensitivity analysis feature. In Phase II, optimization will be added, along with connections to CAD software, a mesh generator, and a display program for stresses and deformations.