Analysis of acoustic radiation of rectangular wooden panels made of spruce, maple and cherry wood

Abstract

Wood is a main component of the forest ecosystem and also a versatile raw material with enormous potential for application. Its application ranges from construction material to an important source of energy. A balanced stand of hardwoods and conifers can be assumed in the future due to the increased establishment of mixed forests. The usage of wood as an environmentally friendly material combines an optimised room aesthetics with mechanical and/or acoustic functionality. Instrument makers have long been aware of the special acoustic properties of wood. This awareness is moving into the interest of transportation. It has an increasing social acceptance. Ultimately, wood is experiencing a renaissance. Cellular materials like wood play an important role in applications where vibration amplitudes and noise need to be reduced. In general, wood is considered to have low damping properties due to its molecular structure and its relatively high modulus of elasticity. Nevertheless, further studies into its acoustic properties are essential in order to be established as an alternative substitute material. In this work, plates made of spruce, maple and cherry wood were mechanically excited in the centre on the back. The acoustic intensity of the panel on the other side was then measured as a spatial function using an acoustic sensor. On the one hand, the results showed a different vibration pattern between the softwood spruce and the hardwoods maple and cherry. On the other hand, the intensity of the acoustic radiation was different. These results were discussed on basis of the structure-dependent damping of wood.