1. What are annoying noises and what are the types?
Annoying noises are sounds that lead to an unpleasant hearing sensation. They need not be loud. A mosquito in the bedroom produces only about 30dB(A) of sonic pressure, but that is extremely disturbing. Annoying noises have the characteristic of being transient. They are considered impulsive and change their frequency and amplitude very quickly. As a result, people perceive them louder as they actually are.
We distinguish between situations in which two sound-reflecting components hit each other and cause rattling (rattle), and situations in which components rub against each other and cause squeaking (squeak). These are material pairings that have a high stick-slip tendency.
There are numerous other noise phenomena, which, depending on the physical state, can be traced back to the same causes.
2. How do annoying noises arise?
The cause of the annoying noises, that mostly occur in vehicle interiors, known as squeak and rattle or BSR, is the relative movement of various components in relation to each other, which is triggered by vibrations while the vehicle is in motion. Annoying noises appear at contact points. If two parts hit each other or rub against each other, annoying noises are the result. Therefore, the search for the core causes of annoying noises is closely linked to the search for relevant contact points.
Due to the electrification of vehicle drives, the noise level in the interior has further decreased, which further increases the audibility of annoying noises.
3. The BSR Analysis
As the global BSR specialist, we offer you all services in the field of annoying noise elimination from a single source, thanks to our experience and with the help of our test benches.
We provide you with the complete solution, from development to series production.
3.1 CAD analysis
For CAD analysis we are involved in an early phase of vehicle development as part of the service.
Using 3D CAD data, we analyalumse the development and uncover potentially critical contact points.
At the same time, we use our stick-slip test rig to examine the corresponding materials for their stick-slip behavior.
Afterwards, the results are evaluated and prioritized.
The customer’s developers implement ZIEGLER’s optimization suggestions and evaluate them as part of a renewed correction loop. The result is a potentially annoying noise-free CAD model. The risk of annoying noises has increased in recent years due to a variety of new materials and customization options.
3.2 Shaker tests
In our acoustics laboratory the prototypes of the components, manufactured on the basis of the CAD data, are checked for rattling and creaking by so-called testing on the shaker, using appropriate test specifications and real excited state. Finally, manufacturing-related aspects can lead to annoying noises, which must be eliminated.
Fault sources are objectively evaluated with our OCIAN System and documented by video recordings. Remedial measures are suggested accordingly.
3.3 Inspection of End-Of-Line Series Production
Certain OEMs and suppliers of the automotive industry perform end-of-line tests on kinematic components in series production. Here, acoustic parameters for all functions are analysed and evaluated for their degree of interference on electrically adjustable seats, electrically extendable displays, electric sunroofs and roller blinds etc., using our specially developed Zound-Lab test system.
4. Why ZIEGLER-Instruments?
Preventive avoidance of annoying noises during the early development phase using the contact point analysis (CPA) method is the most effective and, on balance, the most cost-effective method of preventing creaking noises, squeaking noises and rattling noises on and in the vehicle.
Since we at ZIEGLER-Instruments have been practicing this method for more than 20 years and have refined it again and again, we can now offer this service in a particularly time-saving and therefore cost-effective manner:
Interior systems, such as instrument panels, center consoles, seats etc. within one week
Subsystems or small components within a few days
Complete vehicles within 4 to 6 weeks
Realisation in our premises and on site at the customer
You receive comprehensive documentation on the critical points with prioritization and improvement measures
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5. Industries affected by annoying noises
This issue started with the automotive industry25 years ago. There are extensive test specifications at all OEMs in the automotive industry, which we partly co-authored.
However, we have also worked with other industries because of customer complaints due to creaking, rattling, squeaking and also cracking noises.