Investigation of Dynamic Saint-Venant's Principle in a Cylindrical Waveguide-Experimental and Numerical Results

This paper experimentally and numerically investigates the axial decay of end effects in a cylindrical waveguide under transient loading. End effects, which are defined as an edge response deviating from that of the far field response, are analyzed by applying waves with different spatial distribution on the edge of a waveguide. Four impactors having the same cross-sectional area but different head shapes are impinged upon a long cylindrical waveguide. Surface strains at different locations along the waveguide are recorded and compared. Results from both the experimental and numerical studies indicate that the far field response is not sensitive to the spatial distribution of the applied transient loading. The typical distance beyond which the end effects could be ignored is estimated to be about 2.2 times of the bar radius. These results provide evidence on the existence of dynamic version of Saint-Venant's principle in cylindrical waveguides in high frequency regime.