Numerical simulation of tire rolling noise radiation
|Förderung durch:||Supported by BMBF|
The "numerical simulation of tire rolling noise radiation" is part of the research network "Leiser Straßenverkehr" (silent traffic) which has the aim to reduce the noise emisson of tire road systems about 3dB(A) to 5dB(A). Investigations of road surfaces and tire design concerning sound radiation are two other main pillars of the research project. The numerical tire noise analysis is divided into the pure acoustic simulation part, treated by the Technical University of Hamburg-Harburg department of Mechanics and Ocean Engineering, and the structural-dynamics simulation, developed by the IBNM. The stationary rolling contact problem is solved by an Arbitrary Lagrangian Eulerian (ALE) approach. Subsequently the eigenvalue calculation is executed on the deformed structure. Gyroscopic effects arise and the eigenvalue-problem becomes a wave theory problem. Fig. 1 shows an example of complex eigenvalue analysis yielding a rotating and counterrotating wave (left and right). Neglecting gyroscopic effects results in a vibration (middle) computed in real arithmetics. Fig. 2-4 are eigenforms of a more sophisticated tire model at different frequencies. In Fig. 5 modal superposition with excitation by a the surface of a roller drum test rig is animated in a frequency range up to 760Hz. This tire-modell is rotating with 20km/h. The effective amplitude of the nodes is color-coded with the maximum in the red areas. Future investigations concerning material damping and nonlinear material behaviors at high frequencies have to be done. The developing software tool for numerical rolling noise simulation will contribute to fabricate quiter tires, while simulation during tire developement will show the sound of the later tire. The work is done in close co-operation with the Technical University of Hamburg-Harburg, institute for modelling and computation (acoustics), Continental AG Hannover (tire manufaction and testing) and the Bundesanstalt für Straßenwesen in Bergisch Gladbach.
Figure 1: complex waves and real vibration
Figure 2: gyroscopic eigenform at 106Hz
Figure 3: gyroscopic eigenform at 244Hz
Figure 4: gyroscopic eigenform at 505Hz