Statistical Energy Analysis

Abstract

Statistical energy analysis (SEA) originated in the aerospace industry in the early 1960s. Today, SEA is applied to a large variety of products, from cars and trucks to aircraft, spacecraft, electronic equipment, buildings, consumer products and more. SEA is based on the principle of energy conservation. All the energy input to a system, through mechanical or acoustic excitation, must leave the system through structural damping or acoustic radiation. The method is fast and is applicable over a wide frequency range. SEA is very good for problems that combine many different sources of excitation, whether mechanical or acoustic. In SEA the structural vibrational behavior of elements (subsystems) is described statistically. For high-frequencies a deterministic modal description of the dynamic behavior of structures is not very useful. The modes (oscillators) are grouped statistically and the energy transfer from one group of modes to another group of modes is statistically proportional to the difference in the subsystem total energies. Readers who are interested in a more detailed description of the SEA method are encouraged to read the following interesting literature (Lyon and Maidanik in J. Acoust. Soc. Am. 34(5), pages 623–639, 1962; Ungar in AFFDL-TR-66-52, AF Flight Dynamics Laboratory, Wright-Patterson Air Force Base, OH, 1966; Woodhouse in J. Acoust. Soc. Am. 69(6), pages 1695–1709, 1981). A very clear discussion and explanation of the SEA can be found in Nigam and Narayanan (Applications of Random Vibrations. Springer, Berlin, 1994). SEA is attractive for high-frequency regions where a deterministic analysis of all resonant modes of vibration is not practical.