Investigation on impact noise radiated by the elastic collision of multiple spheres

Abstract

Collision among multiple structures is a major source of noise in industry. To gain a more comprehensive understanding of the collision noise radiated by the impact structures, the collision noise of multiple spheres is measured by an impact device and simulated by a validated numerical model. The numerical model of collision noise radiation is constructed with the explicit nonlinear LS-DYNA3D and the acoustic module in LMS virtual lab. Based on this numerical model, the influence of different factors, including the initial velocity of the impactor, the initial gap, and the number of impactees, on the collision noise radiation of multiple spheres is studied. The numerical results reveal that the amplitude of acoustic pressure is proportional to the initial velocity of the impactor in an elastic collision. It is also found that the initial gap between impactees does affect noise radiation through the acceleration and the noise superposition of spheres. With the increasing number of impactees, the attenuation of noise will slow down.