Investigation of a smart noise barrier for dual active and passive control of construction noise

Construction noise generated from various powered mechanical equipment is mainly dominated by low-frequency sound components. A common practice to this severe noise problem for environmental protection is to block the acoustic transmission path between noise sources and sensitive receivers, in which noise barriers or acoustic enclosures are used to surround construction sites or powered mechanical equipment, respectively. Conventional passive noise barriers are generally made of aluminium, concrete, acrylic sheets or recycled materials, but it is not performed well for low-frequency noise. This research work is concerned with the investigation of a smart noise barrier for both active and passive control of construction noise. This hybrid-based noise barrier is made of two layers, one thick layer is a recylced composite material (i.e., a mixture of wood pellets and rubber particles) and the other one is a polyvinylidene fluoride (PVDF) thin-film. In veiw of the coupling design, the interaction of wood-rubber materials as a resilient layer can achieve good transmission loss at middle and high frequencies for passive noise control. In addition, recycling wood and rubber products into noise barriers is a sustainable technology that not only preserves the use of natural resources and also advances the engineering performance. In terms of active control, motivated by the high-quality piezo-actuator audio technology, PVDF thin-film materials are performed as a noise-cancellation speaker that can migitate the low-frequency components of incident waves. To demonstrate the effectiveness of this dual-function barrier, a scale-down model is designed and tested in the in-house laboratory. Simple fabrication procedures of this barrier are also presented. It is expected that this study will bring a new idea for dual passive and active noise control in open fields that can reduce the impact of contruction noise for better environmental conservation.