Acoustic treatment of panels: Effect of attachment method

摘要

Sound transmission loss of panels can be improved by attaching a layer of material specifically designed to increase the sound transmission loss properties of the system. Such a material finds use in a number of practical applications, such as the treatment of inter-tenancy walls and machinery enclosures. This paper explores the effect different attachment methods have on the sound transmission loss, from fully bonded (glued) to loosely bonded (pinned). This paper also investigates methods of modeling the transmission loss of the system. The acoustic treatment used in this research was a multi-layered sheet consisting of a decoupling foam layer, a mass loaded barrier layer, and an absorptive foam layer incorporating a protective face sheet. The treatment was attached to a plywood panel. Transmission loss measurements were performed on a 1550 × 950mm sample following the intensity method described in ISO 15186-1. A significant variation in the transmission loss of the system was observed between 200 - 2000 Hz, with a trend of increased transmission loss as the attachment stiffness was reduced. Several methods were utilized to model the system with reasonable levels of success. Variations in measured and modeled transmission loss are discussed, and possible reasons for these variations are explored.