Statistical energy analysis of periodic structures

Methods evolved from the study of wave propagation through geometrically periodic media are used to enhance the probabilistic models used in statistical energy analysis (SEA). These enhanced models are based on calculations of the pass bands of typical elements of periodic structures and allow SEA to reflect the highly non-uniform distribution of natural frequencies found in such structures. Moreover, the enhancements do not require substantial reworking of the principal results of SEA, nor do they involve major exercises in computing. They also cater for the important case of structures that deviate from pure periodicity. By way of example the flow of energy between two parts of a ship’s structure is investigated. These investigations contrast the results obtained from an ‘exact’ modal analysis of the structure, normal SEA approaches and that now proposed. The new approach is shown to provide worthwhile improvements in energy flow predictions when compared to traditional SEA. These improvements are applicable to a wide variety of geometrically periodic structures, ranging from off-shore platforms through box girder bridges to satellites.