An improved series expansion method of frequency response function under medium and high frequency excitations

In view of the computational divergence in the series expansion method of frequency response function under medium and high frequency excitations, a new improved algorithm for dynamics system response is proposed. Structural modes are divided into available low order modes and truncated high order modes. The frequency response function of truncated high order modes is expanded by the application of Taylor series on the basis of power series expansion and modal superposition method. According to the coupling characteristics between low order and high order modes to mass and stiffness matrices, the contribution of truncated high order modes to the frequency response function is expressed as the low order mode matrix and system matrix. The present method considers the relation between structure frequency and excitation frequency. The results show that the improved algorithm expands the series expansion method to the range of medium and high frequency excitations, and the calculation accuracy of the frequency response function is improved under the incomplete modal conditions. Numerical results validate that this method is feasible and has good convergence.