Combined Finite Element Analysis and Statistical Energy Analysis in Mechanical Intensity Calculations

Abstract

Local and global energy e ow in structures built up by domains with different rigidities is studied. A combined e niteelementanalysis/statistical energy analysis (FEA/SEA)approach isadvanced wherestifferdomains (with low modal density ) are analyzed using FEA and weaker domains (with high modal density ) are analyzed using SEA. The approach proposed employs an energy-based iterative optimization procedure where the difference between externally supplied active power and the total power dissipated in the structure is minimized. Sectional forces in points connecting the stiff and weak domains are used as design variables. Dynamic substructuring is introduced to reduce the number of degrees of freedom in the e nite element domain during the optimization procedure. The potential to cover a large frequency interval is demonstrated in a numerical example in which the harmonic response of a truck is studied. Nomenclature As = source subsystem area C = damping matrix cg = group wave speed ci = mechanical intensity in direction i D(x ) = dynamic stiffness matrix E = Young’ s modulus Eor{E} = subsystem modal energy vector Ei = average total subsystem i energy F = force vector I = unity matrix