Vibrational characteristics of the embalmed human femur

Abstract

The resonant frequencies and mode shapes of contralateral femurs have been identified by experimental and analytical procedures. Also, the cross-sectional area, centroid, and principal moments of inertia were computed throughout the femur length for both compact and cancellous bone. The resonant frequencies of freely vibrating specimens were identified from transfer function measurements by using a Fourier analyzer. Twenty frequencies were noted in a frequency range of 20 Hz–8 kHz. A mathematical model of the femur consisting of 59 joined uniform segments, with each composed of compact and/or cancellous bone, was analyzed by using a transfer matrix technique. Results of the model enabled classification of the experimental resonances into deformations corresponding to flexure (about principal planes of inertia), torsion, and longitudinal extension with fundamental frequencies at 250, 308, 557, and 2138 Hz, respectively. Generalized non-dimensional resonant frequencies were computed based on femur geometry averaged over its length and compared with those predicted by simple beam models. This analysis provided further understanding of the vibrational behavior of the femur.