Combined finite element analysis and statistical energy analysis in mechanical intensity calculations

Local and global energy flow in structures built up by domains with differe nt rigidities is studied. A combined finite element analysis/statistical en ergy analysis (FEA/SEA) approach is advanced where stiffer domains (with lo w modal density) are analyzed using FEA and weaker domains (with high modal density) are analyzed using SEA. The approach proposed employs an energy-b ased iterative optimization procedure where the difference between external ly supplied active power and the total power dissipated in the structure is minimized. Sectional forces in points connecting the stiff and weak domain s are used as design variables. Dynamic substructuring is introduced to red uce the number of degrees of freedom in the finite element domain during th e 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.