Comparison of Vibration Durability Tests with respect to Fatigue Damage & Validation Study

Abstract

In this study, Random and Harmonic vibration test specifications for Automotive Lighting systems are compared according to their damage content. Harmonic and Random vibration specifications which have different durations and Acceleration Power Spectrum Densities (PSD G) are plotted and compared according to damage accumulated on one degree of freedom (SDOF) system. Outcome of this study is the evaluation of fatigue strength of common or similar parts used on lighting systems which are dedicated to different customers, different car segments; and evaluation of the severity of new customer vibration durability test specifications and evaluation of special design precautions for new design projects. Shorter duration PSD G’s and Harmonic tests which have equivalent Fatigue Damage Spectrums (FDS) can be created and instant design modifications can be tested and evaluated. In addition, in this study, random test time reduction formula was validated with physical tests.

Keywords

• FDS,Random Vibration Test,Sine Sweep Test,Harmonic Vibration Test,Accelerated testing

References

1. Lalanne, C., 2002. “Mechanical Vibration & Shock, Specification Development Volume V” p. 135–137.;p.140
2. Plaskitt, Halfpenny “The Fatigue Damage Spectrum: Explained”, 28th ICAF Symposium- Helsinki, 3-5 June
3. Wei-Lun Chang, Ken-Yuan Lin, Chin-Duo Hsueh and Jung-Ming Chang;Vibration Test Specification Design and Reliability Analysis; SAE International; 2011-01-0491; Published 04/12/2011.