Stephen A. Hambric
Comput. Mech. Div., Code 1282, Carderock Div., NSWC, Bethesda, MD 20084-5000
Research on calculating mechanical power flow quantities (steady-state structural intensities and power dissipation) in finite element models from dynamic forces and velocities output by the NASTRAN computer program is summarized. Mechanical power formulations for the axial, torsional, and bending motion of beams and the membrane and bending motion of plates are presented. The formulations have been implemented in the program McPOW (Mechanical POWer) [S. A. Hambric, J. Vib. Acoust. 112, 542--549 (1990)], which functions as a post-processor to NASTRAN. Results are shown from a study comparing experimental and finite element flexural power measurements for a point excited straight beam with compliant end mounts. The good agreement of the experimental and numerical power spectra serve to validate the finite element mechanical power method. Also, animations of the power flow response of a cantilever plate model over a frequency range encompassing several low- to mid-order flexural and membrane modes were performed on graphics computers and recorded on videotape, and will be presented to show the benefit of visualization techniques in understanding mechanical power analyses.