Industrial applications of the SEA

In [R 6 215], we sketched out the underlying principles of SEA statistical energy analysis, setting out its assumptions and calculation methods in a sometimes sketchy way. The examples presented in this dossier [R 6 216] probably give a partial view of the applicative possibilities, but they are real-life examples that have enabled us to make progress. The principles of analytical calculation, inherited from the 1960s, make AES a method that requires experience. Commercial calculation codes compensate for this, but only in part, as the engineer's time is generally required. The formalism and implicit assumptions conveyed by the method are not as "linear" as those described in a presentation on the finite element method. Nevertheless, SEA, which was very little used until the early 1980s, has gradually established itself as the reference method for calculating random vibrations. Despite its weaknesses, it has proved extremely effective, often giving results just as accurate as deterministic methods described as "exact".

It is currently the only method for building vibro-acoustic "system" models, taking into account the multiplicity of sources and transmission paths. Recent developments in this technique, based on an increasingly extensive use of finite element discretization methods, have widened the field of users. The key problem of partitioning into sub-systems can now be solved with virtual SEA analysis. Automation of this technology could eventually enable direct integration into finite element method development environments. From this point of view, SEA appears as a simple method for post-processing information. It is a compressor for dynamic data of experimental or theoretical origin, enabling a global view of the environment to be restored in the form of a few spectra representing the essential information. As R.H. LYON had already noted, it is perhaps the very essence of the method to provide the path to follow to reduce the entropy of the information of the systems observed.