A Comparison of Different Squeak & Rattle Test Methods for Large Modules and Subsystems 1999-01-0693
Many engineers today use large, powerful multi-purpose test systems to do squeak & rattle testing of modules and subsystems such as Instrument Panels, Consoles and Seat Assemblies. Such test systems include Multi-Axis Hydraulic Shaker Tables and Electrodynamic Vibration Systems with large head expanders and rigid (or at least stiff) fixtures. These test systems have been successful when used for squeak & rattle test programs, have been validated as approved test methods, and have become the standards of comparison in many labs today. They are, however, expensive and throughput can be limited due to the time needed to unbolt, unload, handle, load, and re-bolt a test item at its many attachment points on the rigid fixture. Furthermore, the capital cost of these Legacy systems can be prohibitive, especially for the smaller supplier, who is being compelled to perform squeak & rattle testing on the products they supply to their customers, the vehicle manufacturers and Tier 1 suppliers.
Visteon Automotive Systems in Saline, Michigan, has been using such a Legacy test system for over five years to squeak & rattle test instrument panels and consoles and continues to get excellent results. Increasing demands for improved squeak & rattle performance dictated that they significantly increase throughput and adding another Legacy system was not an option. Previous experimentation revealed that “… Legacy Systems which simulate in-vehicle boundary conditions and which require road-load profiles to be controlled by multi-axis vibration control systems, and the costs associated with these Legacy System solutions, are not necessarily required to find sources of squeaks & rattles …” (SAE 97NV248). Therefore, it was decided to attempt validating, for our production use, this alternative method which had previously been proven feasible. The purpose of this paper is to describe the verification process and the results obtained.