Structural intensity analysis of stepped thickness rectangular plates utilizing the finite element method

Stepped thickness rectangular plates are found in various engineering branches, and knowledge about their dynamic performance represents an important issue for rational structural design. The structural intensity analysis, assessing magnitude and direction of vibration energy flow provides information on dominant transmission paths, and vibratory energy distribution including sink positions. In this paper, vibration energy flow in stepped thickness rectangular plates is analysed by structural intensity technique employing the finite element method. An outline of structural intensity formulation for a plate element is given, and developed analysis system combining in-house code and commercial FE tools is described. Numerical examples include structural intensity analysis of stepped thickness rectangular plates subjected to harmonic excitation forces with different sets of boundary conditions, where special attention is paid to influence of plate thickness ratio variation on vibration energy flow. Moreover, different structural intensity components of a simply supported stepped thickness plate are separately quantified, to assess their contribution to the total intensity.