Presentation of two approved research projects
Rubbing noises can have a very unpleasant psychoacoustic effect on humans, which can directly causes a negative sensation on the perceived quality of cloths or the touched object. Rubbing noises can additionally cause complete functional failures. Contact partners are for example skin to textile, textile to textile, skin or textile to other materials.
Target of the research project is the correlation of material characteristics, emitted noises and psychoacoustic effects of the noise with the human perception and therefore enable the development of products specifically towards emitted noises. Included is the development of a test stand to measure friction coefficient and rubbing noises. With acoustic parameterization the effect of rubbing noises on humans shall be displayed in the form of an annoying grade for rubbing noises.
Currently such equipment for the mentioned specification is not available on the world market. The known stick-slip test stands only determine material characterization. As of now, there was no need to consider the operating noise of the machine. The simultaneous acquisition of the emitted noise will be a whole new dimension.
In automotive manufacturing a variety of seals are being used. Most of the seals are hollow section or lip seals, which are built against different counter materials like painted metal, molded plastic components or glass. Under certain situations stick-slip effects can occur. This is not accepted by the operator and can cause a high cost increase for OEM´s and suppliers due to those claims. With current test methods a real simulation for actual applications is not possible, although those situations can have a significant impact on the squeaking behavior. The actual simulation includes two aspects. On one hand the contact point does vary due to manufacturing tolerances and through the different behavior of the contact partners. On the other hand seals do not only move in one direction but rather move in all three directions within the actual vehicle.
The target is to develop a multi-axis test system, which allows the simulation of the automated contact situations and therefore select a preventive solution with regards to the actual situation within the vehicle. Essential part is not only the development of a corresponding test stand, but also the implementation of a proper measurement methodology. Actual contact situations need to be recorded and simulated realistically in the lab. Target is a test unit that includes the essential influencing parameters for squeaking behavior and also provides the possibility to derive remedial actions to reduce stick-slip. Squeaking noises due to friction shall be eliminated preventively with the help of such system.