Modelling structure-borne sound transmission across a timber-frame wall using SEA

This paper concerns the modelling of sound transmission across a timber-frame wall under mechanical excitation by a point force using Statistical Energy Analysis (SEA). The aim is to develop and experimentally validate a model that would be relevant to machinery such as a heating device or a ventilation system that are often connected to such walls. The prediction is compared against measurements on a wall that forms part of a lightweight test-rig in the Laboratory for Sound Measurement (LaSM) at the University of Applied Sciences Rosenheim. A basic timber frame was built with a single layer of tongue and grooved chipboard on each side of the wall. With this configuration the structure represented a lightweight construction with horizontal junctions in addition to the vertical junctions that are more typical with lightweight constructions formed from plasterboard. A series of SEA models were developed with an increasing degree of complexity regarding the partitioning of the structure into subsystems. Additional experimental work was carried out to determine coupling loss factors across the chipboard joints which were then incorporated in the model. The SEA predictions are compared with measured velocities on both leaves and sound pressure levels in the cavities.