DETERMINATION OF THE STRUCTURAL DAMPING COEFFICIENTS OF SIX FULL-SCALE HELICOPTER ROTOR BLADES OF DIFFERENT MATERIALS AND METHODS OF CONSTRUCTION

摘要

Measurements were made of the internal or structural damping characteristics of six full-scale helicopter rotor blades of six different materials and methods of construction. Structural damping coefficients are presented for the first three flapwise bending modes, the first torsion mode, and the first chordwise bending mode for all blades.nThe structural damping coefficients for all blades are presented in tabular form together with the frequencies, amplitudes of oscilla¬tion, and approximate stresses in flapwise bending. Approximate tor¬sional stresses are also given for one blade. Typical samples of the data are plotted to show effects of material of construction, mode shape, and amplitude on the structural damping coefficients.