The equipment/component elements mounted on the vehicle’s main structure (and/or the components that are in turn mounted on the equipment) pneumatic, electrical and electronic must be tested against random vibration and shock when they go to Install in railway vehicles.
Random vibration tests are the only method that can be used for the approval of the equipment/components.
These tests have as a specific objective to demonstrate the ability of test equipment to withstand the type of ambient vibration conditions normally expected for rail vehicles.
These tests can be carried out in prototypes to obtain design information on the performance of the product subjected to random vibrations. However, for certification testing purposes, these must be carried out on equipment taken from normal production.
Shock and vibration tests are performed to ensure that the quality of the equipment is acceptable, because it must withstand tests of a reasonable duration that simulate the conditions of service to which it is supposed to be exposed during its useful life.
Simulated ageing tests can be performed in several ways, each with advantages and drawbacks, the following being among the most common:
- Amplification: A test in which amplitudes are increased and time duration is reduced;
- Time compression: A test in which the history of amplitude is maintained and the time duration (increase in frequency) is reduced;
- Deleting time intervals: A test in which time intervals of historical data are eliminated when the amplitudes are below a specified threshold value.