Stable Solitary Waves in Granular Alignments

We study the propagation of an impulse in a loaded chain of elastic spheres where the spheres are held between fixed walls. We show that for a certain critical loading, propagating impulses develop into solitary waves and these solitary waves are not measurably affected by wall collisions, the latter being typically the case with granular solitary waves. The properties of these special solitary waves and of possible connections between this problem and the Fermi-Pasta-Ulam problem will be addressed.