To address most of the life cycle situations during which vibration is likely to be experienced on the product.
Vibration results in dynamic deflections of and within materiel. These dynamic deflections and associated velocities and accelerations may cause or contribute to structural fatigue and mechanical wear of structures, assemblies, and parts. In addition, dynamic deflections may result in impacting of elements and/or disruption of function. Some typical symptoms of vibration-induced problems follow. This list is not intended to be all-inclusive: Chafed wiring, Loose fasteners/components, Intermittent electrical contacts, Electrical shorts, Deformed seals, Failed components, Optical or mechanical misalignment, Cracked and/or broken structures, Migration of particles and failed components, Particles and failed components lodged in circuitry or mechanisms, Excessive electrical noise, Fretting corrosion in bearings.
Essentially all materiel will experience vibration, whether during manufacture, transportation, maintenance, or operational use. The procedures of vibration methods address most of the life cycle situations during which vibration is likely to be experienced.
Random Vibration test is conducted for the purpose of determining the ability of component parts to withstand the dynamic stress exerted by random vibration applied between upper and lower frequency limits to simulate the vibration experienced in various service field environments. Random vibration is characteristic of modern field environments produced by missiles, high-thrust jets and rocket engines. In these types of environments, the random vibration provides a more realistic test. For design purposes, however, a swept frequency sinusoidal test may yield more pertinent design information.
The high frequency vibration test is performed for the purpose of determining the effect on component parts of vibration in the frequency ranges of 10 to 500 hertz (Hz), 10 to 2,000 Hz or 10 to 3,000 Hz, as may be encountered in aircraft, missiles, and tanks. The choice of test condition severity should be based on the frequency range and the vibration amplitude dictated by the applications of the component under consideration, and the state of the component part in relation to resistance-to-vibration damage.