EXPERIMENTAL INVESTIGATION OF THE VIBRATIONS OF A BUILT-UP RECTANGULAR BOX BEAM

摘要

Experimental modes and frequencies of a uniform built-up box beam are presented and comparisons are made between experimental and theoreti-cal frequencies. For bending vibrations, frequencies obtained from an analysis of a substitute-stringer structure which includes the influence of transverse shear deformation and shear lag were found to agree very well with those obtained experimentally. In the case of torsional vibra-tions, the frequencies obtained from either an elementary or a four-flange beam analysis which includes the effects of restraint of warping were found to be in satisfactory agreement with the experimental frequencies.