Practical considerations of vehicle noise and vibration simulation using an improved dynamic impedance method

The design of automotive components for low structure-borne interior noise and vibration is facilitated by the ability to reliably simulate total vehicle system response over a wide operating frequency range. This requires that the car body, its interior acoustic cavity, and critical chassis components must be included in the overall dynamic model. Unfortunately, most noise and vibration problems occur in the 200-1000 Hz frequency range where finite element and experimental modal methods have limited applicability. This is due to the high modal density, high damping levels, and sensitivity to fine geometric detail. A simulation method has been proposed earlier which uses component finite element models and component experimental transfer functions to predict combined system response [1]. This method has allowed for a practical approach to automotive system noise and vibration simulation. In this paper, a discussion of various practical concerns in the implementation of the SMART (System Modelling and Analysis using the Response Technique) is presented. A comparison will be made to the approximate system response using the blocked force method, which is sometimes referred to as the Complex Vector method. Insight will be provided to proper model configuration and implementation of Singular Value Decomposition (SVD) filtering using the SMART algorithm. A discussion of potential applications where the approximate Complex Vector method may provide a more accurate prediction than the full SMART algorithm is also provided.