PSEUDO-MODAL REPRESENTATIONS OF LARGE MODELS WITH VISCOELASTIC BEHAVIOR

摘要

Damping augmentation materials and devices are often characterized by a frequency dependent complex modulus. The present study focuses on the prediction of the effects of damping treatments on complex structures which can only be modeled with large finite element models. For such models, the inversion of the dynamic stiffness at each frequency point of interest is not a viable approach. Reduction procedures similar to the modal truncation used for elastic structures are thus essential. The paper introduces a robust approach based on a projection on the basis of pseudo-normal modes which correspond to singularities of the conservative part of the dynamic stiffness. The accuracy achieved by this method is demonstrated for a 440 DOF model of a windshield bonded to a rigid frame by a viscoelastic material.