Use of the Finite Element Damped Forced Response Strain Energy Distribution for Vibration Reduction.
Final rept. Jul 71-Jul 74,
BOEING VERTOL CO PHILADELPHIA PA
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Analysis has previously been developed verifying that a minimum weight structure with a specified natural frequency is one wherein the density differential strain energy density less kinetic energy density is uniform throughout the structure when deformed in its natural mode. Using the convenience of the finite element method, the density differential or as an approximation, the strain density of each structural element may be obtained for a given natural mode. This concept is extended here from the modal method to a damped forced response method wherein the strain density is determined for all the structural elements acting under a steady state vibratory loading. Application of energy methods to vibration reduction of the Boeing Vertol Model 347 Tandem Helicopter is shown. Advantages of the damped forced response method as well as other applications are given.