Studies of the dynamic behaviour of two machine assemblies with particular respect to noise reduction at the design stage

The general aim of this thesis has been to demonstrate how noise could be reduced at the design and development stages of industrial machinery by effective engineering design. Part A embodies the general methods of noise generation mechanism and principles of noise control. The case studies having entirely contrasting noise problems are presented in Parts B and C, where advanced experimental techniques such as dynamic strain measurement, hologram interferometry and high-speed photography have been used for analysis purposes. The first case study is made on a textile machinery drawroll assembly (Part B) in which a drawroll radiates much of the noise at a single frequency. The drawroll is reciprocated by the fundamental longitudinal mode of vibration of the assembly which is excited by small impactive but random forces at its gear drive. [Continues.]