Vibrations and noise of textile loom picking sticks

Abstract

Recent experimental work suggests that picking-stick vibrations are a dominant source of noise from fly-shuttle-type textile looms. A picking stick is modeled as a beam with internal damping. Impacts from the incoming shuttle are modeled by assuming the shuttle to be a rigid body with mass M and initial velocity V0 just prior to impact. The energy transfer during impact to higher-frequency vibrations of the beam is treated approximately by ignoring wave reflections from the far end of the beam, and a correspondingly simple expression is derived for the net energy transferred within any frequency band during a single impact. This energy is subsequently assumed to be distributed among the vibrational modes within the corresponding frequency band but to be relatively quickly dissipated by transmission out of the beam to other parts of the beam and by internal damping. However, during the time the energy is present, the beam is vibrating and radiating sound. The resulting sound radiation is computed based on a modification of the theory of sound generation by transversely oscillating slender bodies.