The aim of this paper is to provide an overview the existing industrial practices used for cabin noise control in various industries such as automotive, marine, aerospace, and defense. However, emphasis placed on automobiles armored vehicles. Generally, automobile cabins usually constitute thin structural panels, where fundamental frequency typically falls below 200[Formula: see text]Hz. If a specific mode couples with acoustic cabin, booming occurs. As such, discomfort may be felt by...

Recent works have demonstrated the potential of small-scale membrane-type acoustic metamaterials for low-frequency (<500 Hz) noise control. Such a phenomenon is attributed to resonant behavior overhanging membrane in each unit cell. Considering industrial applications, large-scale designs may be preferred. This study presents (0.8 × 0.8 m2) metamaterial (or meta-panel), which was evaluated experimentally and verified numerically. Experimental results showed that broadband sound...

Membrane-type acoustic metamaterials generally involve a heavy platelet attached to pretensioned membrane. Their acoustical performance is characterised solely based on the resonant behaviour of membrane-platelet assembly. However, typical designs may pose manufacturing issues if extended in scale for industrial applications. Examples include spatial consistency platelet(s), uniformity membrane pretension, and durability membrane—not mention stress relaxation. As large-scale are recently...

Abstract In densely populated cities, residents living near aerodromes may experience heightened exposure to aircraft noise. With hybrid work arrangement, authorities have observed a rise in the number of complaints filed by affected view this problem, urban planners are now placing even more emphasis on exploring solutions that can manage noise new and existing residential areas. To achieve objective, usually rely external acoustic consultants generate maps using commercial software....

For industrial applications, the scalability of a finalised design is an important factor to consider. The scaling process typical membrane-type acoustic metamaterials may pose manufacturing challenges such as stress uniformity membrane and spatial consistency platelet. These could be addressed by plate-type with internal tonraum resonator. By adopting concept modularity in large-scale (or meta-panel), acoustical performance different specimen configurations scaled modularly combined. This...

Natural fibres have been extensively studied due to their potential in a wide range of applications. This study aims demonstrate the viability composite earmuffs for low-frequency noise reduction continuous and transient environments. Pink aircraft take-off exterior were considered former latter, respectively. The assembly components kept identical commercial earmuff, which served as reference results comparison. Based on profile ear cups from fabricated coir fibre coir/carbon fabrics...

This study aims to tackle the challenge of high noise levels on balconies while preserving natural ventilation. Eight innovative balcony designs, incorporating elements like diffuser edges, undulating ceilings, Helmholtz resonators, grooves, or sound traps, were evaluated via finite element (FE) modeling. The insertion loss results showed that for many reduction in could deteriorate beyond an elevation 8 m. However, front jagged and full wavy ceiling designs shown be more robust attenuation...

Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, risk auditory damage is still imminent because devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative material selection ear cups earmuffs, which typically made acrylonitrile butadiene styrene (ABS). Different weaving...

In this work, the acoustic damping performances of multiple double- and single-layer perforated liners are experimentally numerically evaluated. These associated with different open-area-ratios, thus enable porosity effect to be studied. Controllable joint bias-grazing flow is applied liners. This simulates configurations a real engine system involving both bias grazing flow. The performance these characterized by power absorption or transmission loss coefficient. Such coefficient measured,...

To develop sustainable cities, natural ventilation is being explored as one of the ways to reduce energy consumption and carbon dioxide emissions. Recently, acoustic metamaterials with have garnered attention for their potential provide both noise control. In addition, this class can be used a machine enclosure dissipating thermal load reducing emission. This presentation focuses on recent progress in over last five years, highlighting three types: metamufflers, metapanels, metacages....

Although the COVID-19 pandemic has now become an endemic, working remotely for certain days of week remains adopted in many companies as norm. As air traffic is heavier during office hours, residents staying near to airport may suffer adverse effects aircraft noise exposure relating productivity and health. this problem present cities, prediction important aiding urban planning processes identify manage accordingly. This paper presents our recent work on adding a new feature-important...

This study aims to tackle the challenge of high noise levels on balconies while preserving natural ventilation. Eight innovative balcony designs, incorporating elements like diffuser edges, undulating ceilings, Helmholtz resonators, grooves, or sound traps, were evaluated via finite element (FE) modeling. The extensive FE studies involved about 10 million per analysis case. Results showed that a standard with front parapet wall could achieve reduction around dBA, jagged ledge design...