When a vehicle drives over road seams or a bumpy surface, low-frequency noise called drumming is generated, causing driver discomfort. The generation of drumming noise is closely related to the vibration characteristics of the suspension, body frame, and body panels, as well as the acoustic characteristics of the vehicle interior. It is therefore difficult to take measures to get rid of drumming after the basic vehicle construction has been finalized. Aiming to ensure drumming performance in the drawing review phase, we applied the Finite Element Method (FEM) to obtain acoustical transfer functions of the body, and Multi Body Simulation to get suspension load characteristics. This paper presents the results of the study of drumming prediction technology using this hybrid approach.
The paper also describes the results of 1) analyzing actual driving behavior when drumming occurs using a multi-point simultaneous measuring system, 2) analyzing suspension vibration characteristics as a cause of drumming, and 3) validating the correlation between the FEM model and an actual vehicle using Robot-controlled 3D Scanning Laser Vibrometers. Modifications made to the actual body structure are also introduced as a case study on effective drumming reduction.