Failure analysis of a vibration isolator used in launch vehicle applications

• Failure analysis of mission critical vibration isolators used in satellite launch vehicles is presented.
• Micro cracks formed during the deep drawing operation due to large strains at fore end corner propagated during testing resulting in the failure of vibration isolator.
• It is recommended to use deep drawing grade material in fully annealed condition to avoid the recurrence of such failures.

Vibration isolators are used in launch vehicles to protect sensitive electronic equipments from the rigors of flight structural vibrations during the lift-off and ascent phase. Failure of one such vibration isolator made of AISI 304 is reported in the present study after ground level testing has been completed. The vibration isolator had a crack of length approximately 42 mm at the fore end corner. Detailed optical and scanning electron microscopy was conducted on the failed vibration isolator to understand the reasons for cracking. Finally, it was concluded that micro cracks formed during the deep drawing operation (due to large strains at the fore end corner) propagated during vibration testing resulting in the failure of the body of the vibration isolator.