Effect of Initial Stress on the Propagation of Flexural Waves in Elastic Rectangular Bars

Abstract

The dynamics of continuous media subjected to initial stress is of great interest in several fields of applied science and technology: geophysics, oceanography, underwater acoustics, and structural design. Pioneering analytical work in this field was done by Biot. Few contributions have been made, however, to the experimental treatment of the problems of determining dynamic stress distributions within statically prestressed continuous media. The present paper deals with an experimental analysis of the propagation of flexural waves in prismatic elastic bars with and without prestressing. A complete, direct, full-field optical determination of dynamic stress distributions associated with the flexural waves is obtained by a combination of photoelastic and interferometric measurements. The effects of prestressing by axial tension, axial compression, and pure bending are illustrated. Comparisons are made with an approximate theory. The results are extended to bars of other materials by scaling laws.