A computationally-efficient numerical model to characterize the noise behavior of metal-framed walls

Architects, designers, and engineers are making great efforts to design acoustically-efficient metal-framed walls, minimizing acoustic bridging. Therefore, efficient simulation models to predict the acoustic insulation complying with ISO 10140 are needed at a design stage. In order to achieve this, a numerical model consisting of two fluid-filled reverberation chambers, partitioned using a metal-framed wall, is to be simulated at one-third-octaves. This produces a large simulation model consisting of several millions of nodes and elements. Therefore, efficient meshing procedures are necessary to obtain better solution times and to effectively utilise computational resources. Such models should also demonstrate effective Fluid-Structure Interaction (FSI) along with acoustic-fluid coupling to simulate a realistic scenario. In this contribution, the development of a finite element frequency-dependent mesh model that can characterize the sound insulation of metal-framed walls is presented. Preliminary results on the application of the proposed model to study the geometric contribution of stud frames on the overall acoustic performance of metal-framed walls are also presented. It is considered that the presented numerical model can be used to effectively visualize the noise behaviour of advanced materials and multi-material structures

Fundamentals of laser powder bed fusion of metals, 1st Edition, Elsevier (2021), p. 676, Igor Yadroitsev, Ina Yadroitsava, Anton Du Plessis, Eric MacDonald, ISBN: 9780128240908 [book review]

© 2001 The Author. Published by Elsevier This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website:https://doi.org/10.1016/j.aime.2022.100070Accepted versio

Acoustic absorption of passive destructive interference cavities

Acoustic products are primarily designed for broadband acoustic absorption. However, frequency-dependent acoustic absorption featuring passive design-based solutions are necessary to combat the growing noise pollution. Accordingly, this research investigates the targeted creation of sound absorption as a function of geometry utilising the principle of Acoustic Interference (AI). A methodology to design freeform geometries that can create targeted acoustic absorption is presented. The effectiveness of this methodology is then experimentally validated while quantifying the influence of length, diameter and geometry orientation. The results establish that AI has the potential to create ‘near perfect’ sound absorption that can be customised depending on the source frequency. The design freedom revealed by this study allows the exploitation of freeform geometries as passive high-efficiency sound absorbing devices

High-temperature oxidation and erosion of HVOF sprayed NiCrSiB/Al2O3 and NiCrSiB/WC Co coatings

© 2021 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1016/j.apsadv.2021.100191Material deterioration due to erosion and oxidation in high-temperature environments is a major cause of wear in power plants, aircraft engines and petrochemical industries. NiCrSiB based surface coatings using thermal spray techniques such as High-Velocity Oxy-Fuel (HVOF) offer a cost-effective route to improve the tribological properties for a range of substrate materials. The study investigates the high-temperature oxidation and erosion resistance of HVOF coated NiCrSiB reinforced with Al2O3 and WC single bond Co on SS304 stainless steel substrate. The oxidation kinetics and erosion responses of the coatings at 750 °C were evaluated for a period of 160 hrs and the coating microstructure, morphology and chemical compositions characterised. A total of three coating compositions were studied namely: NiCrSiB/Al2O3, NiCrSiB/n-Al2O3 and NiCrSiB/WC single bond Co where the results indicate a superior oxidation and erosion resistance in all cases in comparison to uncoated SS304. However, it was found that the NiCrSiB reinforced with micro-structured Al2O3 outperformed all the other coatings in terms of oxidation resistance. When it comes to erosion resistance, NiCrSiB/WC single bond Co was found to demonstrate the highest performance.Accepted versio

Acoustic behaviour of 3D printed titanium perforated panels

© 2021 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1016/j.rineng.2021.100252Titanium alloys such as Ti6Al4V is amongst the most widely studied metallic materials in the broad context of metal 3D printing. Although the mechanical performances are well understood, the acoustic performance of 3D printed Ti6Al4V, and Ti6Al4V ELI (Extra Low Interstitial) has received limited attention in the literature. As such, this study investigates the normal incidence sound absorption coefficient () and Sound Transmission Loss (STL) of both Ti6Al4V and Ti6Al4V ELI samples manufactured using Selective Laser Melting (SLM). The influence of material thickness on acoustic responses and the potential of developing Ti6Al4V micro-perforated panels (MPP) at 400–1600 Hz is also explored. The sound absorption of three aesthetic perforations printed using Ti6Al4V and the influence of a porous back layer was also investigated. The experimental measurements were carried out using an impedance tube following ISO10534-2. The result of the study establishes that 3D printed non-circular perforations featuring porous back-layer can exhibit improved sound absorption coefficient.This research was funded by the European Commission CALMERIC Grant 32R19P03053.Accepted versio

Perforated steel stud to improve the acoustic insulation of drywall partitions

©2021 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/acoustics3040043Steel studs are an inevitable part of drywall construction as they are lightweight and offer the required structural stability. However, the studs act as sound bridges between the plasterboards, reducing the overall sound insulation of the wall. Overcoming this often calls for wider cavity walls and complex stud decoupling fixtures that increase the installation cost while reducing the floor area. As an alternative approach, this research reveals the potential of perforated studs to improve the acoustic insulation of drywall partitions. The acoustic and structural performance is characterized using a validated finite element model that acted as a prediction tool in reducing the number of physical tests required. The results established that an acoustic numerical model featuring fluid-structure-interaction can predict the weighted sound reduction index of a stud wall assembly at an accuracy of ±1 dB. The model was used to analyze six perforated stud designs and found them to outperform the sound insulation of non-perforated drywall partitions by reducing the sound bridging. Overall, the best performing perforated stud design was found to offer improvements in acoustic insulation of up to 4 dB, while being structurally compliant.Published onlin