ASA 125th Meeting Ottawa 1993 May

2pNS6. Vibroacoustical design for the connecting structure between a vibrating source and a lightweight envelopping structure.

Nicolas Lessard

Frederic Laville

Francois Charron

Mech. Eng. Dept., Univ. de Sherbrooke, 2500 Boul. Universite, Sherbrooke, PQ J1K 2R1, Canada

This research is on the design of the connecting structures between a vibrating source and a lightweight structure with application to ventilation devices with a 120-Hz excitation by an electrical motor. The design method had two objectives: a low noise level and little variability in level (robust design). Three complementary approaches have been used to identify the various design, manufacturing, and assembling parameters that affect the low-frequency noise level. First, acoustical engineering judgment lead to basic design concepts. Two other approaches were then used to analyze the effect of these basics design concepts and various manufacturing and assembly parameters on the noise level. The first approach was a statistically designed experimentation to identify key parameters. The second approach was a finite element modelization including a sensitivity analysis of the quadratic velocity as a function of key parameters. The design approach applied to the case of an electrical motor in a box-like structure lead to the choice of a low-noise connecting structure as well as the identification of important manufacturing and assembly parameters to be controlled to ensure a low noise variability.