Smooth Operator

This article reviews finite element analysis (FEA) that helped Boeing to eliminate oiled bearings on its Chinook helicopter. The pitch-hinge assembly on the helicopter permits the blade to rotate on its longitudinal axis and to control thrust, which determines where the helicopter is going. In other words, it dictates the pitch of the rotor blades and is one of the most important hinges on the craft. About 2 years ago, Boeing sought to redesign the pitch-hinge assembly to replace the bearings with a self-lubricated hinge. FEA is the use of a complex system of points, called nodes that form a grid, or mesh, across a computer-aided design model. The mesh contains the material and structural properties that define how the part will react to certain load conditions. In essence, FEA is a numerical method used to solve a variety of engineering problems that involve stress, heat transfer, electromagnetism, and fluid flow.