Vibration testing - Measuring and using results

Vibrations are an integral part of our universe. The slightest movement generates vibrations of varying amplitude and duration, from the slow oscillation of a suspension bridge excited by the wind, to the shock of an aircraft landing, to the noise of our car engines. This vibratory environment is felt by all the equipment we use in everyday life, and can lead to malfunctions or even the destruction of the equipment in question.

This gave rise to the need to certify structures through a series of tests representative of the vibration environment encountered by a product throughout its life cycle. The great diversity of situations encountered generates a wide range of tests of very different natures, requiring the operator of a vibration test to use equally diverse measuring equipment.

The aim of this article is to help the neophyte understand the important factors to consider when choosing measurement equipment, and then, based on the results obtained, how to exploit them while avoiding the pitfalls of misinterpretation.

After a brief review of a few principles of structural dynamics, the different types of vibration tests are discussed, highlighting their specific features in terms of both measurement parameters and results processing.

The different components of an acquisition chain are then detailed, as it is necessary to understand the advantages and disadvantages of the various pieces of equipment in order to make an appropriate choice. Interpreting measurement results is an essential step, as you can only use what you know how to interpret.

For information purposes, the chronology of a vibration test is traced, allowing each stage to be seen in a concrete context.