AN OPTIMIZATION APPROACH TO IMPROVING EIGENVALUES OF LIGHTWEIGHT BEAMSTRUCTURES

This paper presents a structural optimization approach to reduce vibra tion, which is a key issue in the structural design of components for head positioners. This method can be used in the concept design stage of head arms for hard disk drives. Head arm vibration modes that affec t the accuracy of head positioning are discussed to obtain the feasibl e design domain of eigenvalues. An optimization algorithm based on a p rojection method is formulated to obtain the shape with the maximal ei genvalue under a constant weight. The formulation is applied to a prim itive head arm model, simultaneously considering the bending mode and the lateral bending mode. The conditions for maximization of the eigen values are not the same for both modes. This paper treats the vibratio n problems of head arms and shows that a feasible domain of natural fr equencies can be found for any given weight.