Abstract: FEA model representing a product made of at least in-part frequency-dependent material and subjected to external harmonic excitations in a range of external excitation frequencies is received in a computer system. The range of frequencies is partitioned into N frequency bands based on predefined criteria. In each frequency band, a representative frequency is selected for calculating the material properties and an eigensolution frequency range is determined for establishing upper and lower limits of subsequent eigensolution. N eigensolutions (one for each frequency band) are performed to extract natural vibration frequencies and associated mode shapes of the product. Depending upon which one of the N frequency bands each of the external harmonic excitations is located, a corresponding set of extracted natural vibration frequencies and mode shapes is selected and used in a modified mode-superposition technique to obtain steady-state dynamic (SSD) responses of the product.