SAE Vibration Test for Motor Vehicle Lighting Devices and Components

A new laboratory test specification was developed through vibration measurements at various locations on selected vehicles including trucks. Various alternatives for laboratory test equipment and test procedures were also studied. While the new specification addresses two major shortcomings of the previous test - repeatability and improved correlation of loads between the field and the test - it is not possible for a single vibration test to represent the vibration spectrum for all lamps mounted at all locations for all vehicles including heavy trucks. Because there are many manufacturers of lighting components - some of which are relatively small companies, only relatively simple and readily available vibration test equipment was considered for the new procedure.

For some of the passenger car locations, the measured vibration amplitude was only one-sixth the vibration level specified in this specification. However, because many lighting devices are designed and manufactured for general usage, the vibration spectrum for the laboratory test was selected to approximate the highest measured levels. Multiple test levels would be required to better approximate the vibration spectrum for all vehicles. This was judged not to be necessary, however, because lamp design is generally not dictated by fatigue life considerations.

While this laboratory test specification does not provide complete correlation between the laboratory and the field, it is sufficient to detect major design deficiencies and structural flows and is compatible with commercially availalbe equipment.