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Published March 2013 | public
Journal Article

Directional Wave Propagation in a Highly Nonlinear Square Packing of Spheres


We studied the dynamic response of a two-dimensional square packing of uncompressed stainless steel spheres excited by impulsive loadings. We developed a new experimental measurement technique, employing miniature tri-axial accelerometers, to determine the stress wave properties in the array resulting from both an in-plane and out-of-plane impact. Results from our numerical simulations, based on a discrete particle model, were in good agreement with the experimental results. We observed that the impulsive excitations were resolved into solitary waves traveling only through initially excited chains. The observed solitary waves were determined to have similar (Hertzian) properties to the extensively studied solitary waves supported by an uncompressed, uniform, one-dimensional chain of spheres. The highly directional response of this system could be used as a basis to design granular crystals with predetermined wave propagation paths capable of mitigating stress wave energy.

Additional Information

© 2011 Society for Experimental Mechanics. Received: 16 July 2011; Accepted: 29 August 2011; Published online: 6 October 2011. We thank Dr. A. Spadoni for his suggestions in the design of the confining box used in experiments. We also thank R. Giordano and A. Esposito for their preliminary work on the subject. This work was supported by an award from the Department of Energy Office of Science (DOE SCGF) and the Army Research Office MURI (Dr. David Stepp).

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October 23, 2023