A Systematic and Disciplined Process for Developing Drive Files for Squeak and Rattle and Durability Tests in the Lab 2009-26-0048

The pressure to shorten vehicle product development time-to-launch means more in-lab tests must be performed earlier, and before vehicle prototypes are available for road or test track evaluations. Squeak and Rattle (S&R) evaluations of subsystems/modules and components must be performed using realistic road excitation conditions. How S&R performance degrades as the vehicle, module or component accumulates customer miles or kilometers must be assessed before the design is frozen. Durability tests must be performed earlier in the design/development timeline as well.

All these pressures point to having a systematic, disciplined and streamlined methodology or protocol for acquiring and processing road vibration data useful for S&R and durability tests. The protocol must comprehend data acquisition, sampling, and signal processing; properly editing acceleration time histories for either in-lab replication as time histories or as PSD random vibration; creation of drive files that replicate multiple road surfaces; combining multiple road surfaces and speeds into fewer (if not one) tests that replace one-test-for-one-road-condition approaches; selecting overall vibration amplitudes for composite multiple roads; and performing such tests in order to satisfy S&R and durability experts, design/release engineers seeking design validation, and multiple other stakeholders.

This paper presents such a protocol based on the expertise from different engineers working on a multitude of vehicle development programs from different companies in different countries over many years.