Development and production processes of vibro-acoustic metamaterials for lightweight vehicle construction
In vehicle development, the demands for energy efficiency through weight reduction conflict with the desire for high noise and vibration comfort. This conflict is particularly evident in electrified vehicles. On the one hand, there is a lack of masking noise from the combustion engine in the lower frequency range, and on the other hand, high-frequency tonal noise components occur that are perceived auditorily by the vehicle occupant. In addition, the weight of the vehicle increases due to additional components, especially the drive battery. This results in increasing lightweight requirements for the rest of the vehicle and thus an intensification of the above-mentioned conflict of objectives.
So-called vibro-acoustic metamaterials are intended to resolve this conflict. Vibro-acoustic metamaterials consist of spring-mass systems periodically attached to the object. This arrangement allows metamaterials to reduce vibrations in the form of stop bands in a predetermined frequency range to a greater extent than conventional methods while adding little weight. Since this also allows a reduction in weight without deterioration of the vibro-acoustic properties, the trade-off between very slim, lightweight structures and optimum comfort can thus be resolved.
The viaMeta project realizes a holistic, virtual development strategy involving vibro-acoustic metamaterials. Their physical modeling will be replicated and optimized. The components are manufactured in a scalable production process and validated by new methods.
In addition to requirements development, the Institute of Automotive Engineering at RWTH Aachen University is involved in the methods of virtual optimization & validation and validates the vibro-acoustic properties experimentally. Specific test benches at both component and system level are first used to check the extent to which established correlation and optimization methods are suitable for validating the simulation models. Based on this, an adaptation of the methods to the requirements of the use case and the use of new approaches will be developed. The findings from the investigations at component and system level and from the validation of the corresponding models will be transferred to the complete vehicle. The suitability of the transfer path analysis methods are also to be tested for applicability and, if necessary, adapted to allow prediction of airborne and structure-borne noise in the vehicle interior. The final vibro-acoustic measurement of a whole-vehicle test vehicle is the basis for validating the simulation models at vehicle level and for verifying the effectiveness of the metamaterials.