Narrow-band random vibration test example with frequency sweep
Test overview
■ Purpose
JIS C 75062-2 “Automotive lamps – Part 2: Performance requirements” describes the items for evaluating vibration resistance and the test conditions, including a narrow-band random vibration test in which the vibration frequency is swept to check whether the light source continues to function during and after the application of vibration.
■ EUT
Car light bulbs
Test condition
JIS C7506-2(2015) Appendix B Section B1.1.2 Heavy Duty Test Conditions
1) Frequency test: 30 Hz to 1050 Hz
2) Bandwidth: 100 Hz
3) Sweep range: 80 Hz to 1000 Hz
4) Sweep speed: 1 octave/min
5) Sweep time: 7.3 minutes
6) A.S.D. spectrum:
80 Hz to 150 Hz 34.57 m2/s4/Hz
150 Hz to 1000 Hz 8.64 m2/s4/Hz
7) Acceleration tolerance: ±1 dB
8) Test time: 20 hours
Test detail
Using software for random-on-random testing, the base ASD level was set to an extremely small level compared to the test level.
By creating a program that superimposed narrowband random vibration components in line with the target values specified in the standard on this base random vibration, we were able to achieve a test that swept a pseudo-random vibration component with a fixed bandwidth.
