On the accuracy of the Timoshenko beam theory above the critical   frequency: best shear coefficient
  We obtain values for the shear coefficient both below and above the critical frequency by comparing the results of the Timoshenko beam theory with experimental data published recently. The best results are obtained, by a least-square fitting, when different values of the shear coefficient are used below and above the critical frequency. 
J. A. Franco-Villafa\~ne and R. A. M\'endez-S\'anchez
physics.class-ph