Calculation of Vibro-Acoustic Frequency Response Functions Using a Single Frequency Boundary Element Solution and a Padé Expansion

This paper presents a new technique to calculate the acoustic field generated by a vibrating body over a frequency interval [f ₁, f ₂]. The solution is based on the calculation of the acoustic response at a central frequency f ₀ by a classical boundary element technique and on an extension of this solution to the whole frequency interval using a Padé approximation of the frequency response function. The Padé approximation requires the knowledge of the successive derivatives of the acoustic field with respect to frequency. The paper describes the technique used to evaluate these derivatives and compares the solution of this new algorithm to results obtained by a classical all-BEM frequency sweep technique. Comparison are made both in terms of accuracy and in terms of computational resources needed for the calculation.