Arun Arjunan | University of Wolverhampton (original) (raw)

Papers by Arun Arjunan

Materials

Efficient and power-dense electrical machines are critical in driving the next generation of gree... more Efficient and power-dense electrical machines are critical in driving the next generation of green energy technologies for many industries including automotive, aerospace and energy. However, one of the primary requirements to enable this is the fabrication of compact custom windings with optimised materials and geometries. Electrical machine windings rely on highly electrically conductive materials, and therefore, the Additive Manufacturing (AM) of custom copper (Cu) and silver (Ag) windings offers opportunities to simultaneously improve efficiency through optimised materials, custom geometries and topology and thermal management through integrated cooling strategies. Laser Powder Bed Fusion (L-PBF) is the most mature AM technology for metals, however, laser processing highly reflective and conductive metals such as Cu and Ag is highly challenging due to insufficient energy absorption. In this regard, this study details the 400 W L-PBF processing of high-purity Cu, Ag and Cu–Ag all...

Free-standing flat screen partitions are commonly used in open-plan environments to improve the v... more Free-standing flat screen partitions are commonly used in open-plan environments to improve the visual and acoustic privacy of employees and to differentiate individual work spaces. Acoustic behaviour of flat screen single leaf barriers under free-field conditions have been extensively studied over the past years. However, the behaviour of free standing structures in enclosed spaces are not fully investigated and hence any opportunities for geometrical improvements such as damping effect of added curvature has not been considered. Curved structures are known to exhibit different stiffness behaviour compared to flat structures of similar global dimensions. Consequently, this work is an initial attempt to understand the acoustic performance of free-standing curved screens in comparison with flat screens of similar global dimensions simulated in an open-plan but enclosed environment. Vibroacoustic simulation using the Finite Element Method (FEM) is used in this study to predict the aco...

Additively manufactured (AM) titanium products are increasingly being used in the aerospace indus... more Additively manufactured (AM) titanium products are increasingly being used in the aerospace industry where the acoustic-mechanical performance is of importance. However, the acoustic performance of AM Ti6Al4V and Ti6Al4V ELI (Extra Low Interstitial) has received limited attention in literature. Accordingly, this study investigates the sound absorption coefficient () and Sound Transmission Loss (STL) of both Ti6Al4V and Ti6Al4V ELI samples manufactured using Selective Laser Melting (SLM). Furthermore, the potential of developing Ti6Al4V alternatively shaped micro-perforated panels (MPP) within a frequency range of 400 to 1600 Hz is also explored.

The European directives on noise reduction associated with buildings, rail, road and aviation cle... more The European directives on noise reduction associated with buildings, rail, road and aviation clearly depicts the need for high efficiency sound attenuating structures for targeted noise reduction . Accordingly, this paper presents key observations from Phase 1 of the UK Department of Transport (DfT) funded research to investigate the targeted creation of acoustic interference to develop high-efficiency noise reducing structures. Geometrical cavities inspired from existing theories around the Herschel-Quincke concept is experimentally investigated for the creation of frequency dependent acoustic interference. The interference cavity within a global structure was digitally conceived and prototyped using the Selective Laser Sintering (SLS) process in a Nylon 12 material. A modified impedance tube method was then used to measure the frequency dependent Sound Reduction Index (R) for a frequency range of 250 to 1600 Hz. The results showed that depending on the frequency of interest, acou...

Acoustic bridging through structural links is known to reduce the Sound Transmission Loss (STL) o... more Acoustic bridging through structural links is known to reduce the Sound Transmission Loss (STL) of gypsum plasterboard partition walls with steel studs. As multifamily housing become more popular, stud manufacturers are increasingly interested in improving the acoustic characteristics of steel studs to improve the sound insulation. This work is an initial attempt to understand the influence of slotted stud configurations on the sound transmission loss (STL) of partition walls. A case of partition wall commonly known as the double-leaf wall incorporating various slotted stud designs are analysed numerically based on the ISO10140 guidelines. The numerical model used for the analysis is validated using experimental test at one-third-octave bands for a frequency range of 100 to 3150 Hz. The slot configurations are designed keeping the slot to non-slot area constant to identify the effect of slot location on the acoustic behaviour. The results of this study provide a better understanding...

COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicro... more COVID-19 pandemic and associated supply-chain disruptions emphasise the requirement for antimicrobial materials for on-demand manufacturing. Besides aerosol transmission, SARS-CoV-2 is also propagated through contact with virus-contaminated surfaces. As such, the development of effective biofunctional materials that can inactivate SARS-CoV-2 are critical for pandemic preparedness. Such materials will enable the rational development of antiviral devices with prolonged serviceability reducing the environmental burden of disposable alternatives. This research reveals the novel use of Laser Powder Bed Fusion (LPBF) to 3D print porous Cobalt-Chromium-Molybdenum (Co-Cr-Mo) superalloy with potent antiviral activity (100% viral inactivation in 30 mins). The porous material was rationally conceived using a multi-objective surrogate model featuring track thickness (tt) and pore diameter (ϕd) as responses. The regression analysis found the most significant parameters for Co-Cr-Mo track formati...

Journal of Hydrodynamics, 2021

This is an accepted manuscript of an article published by Springer in Journal of Hydrodynamics on... more This is an accepted manuscript of an article published by Springer in Journal of Hydrodynamics on 8/11/2021, available online at: https://doi.org/10.1007/s42241-021-0090-0 The accepted version of the publication may differ from the final published version. For re-use please see the publisher's terms and conditions: https://www.springernature.com/gp/open-research/policies/accepted-manuscript-termsUnderstanding the near boundary acoustic oscillation of microbubbles is critical for the effective design of ultrasonic biomedical devices and surface cleaning technologies. Accordingly, this study investigates the three-dimensional microbubble oscillation between two curved rigid plates experiencing a planar acoustic field using boundary integral method (BIM). The numerical model is validated via comparison with the nonlinear oscillation of the bubble governed by the modified Rayleigh-Plesset equation and with the axisymmetric model for an acoustic microbubble in infinite fluid domain. Then, the influence of the wave direction and horizontal standoff distance (h) on the bubble dynamics (including jet velocity, jet direction, centroid movement, total energy, and Kelvin impulse) is evaluated. It was concluded that the jet velocity, the maximum radius and the total energy of the bubble are not significantly influenced by the wave direction, while the jet direction and the high-pressure region depend strongly on it. More importantly, it was found that the jet velocity and the high-pressure region around the jet in acoustic bubble are drastically larger than their counterparts in the gas bubble

Applied Surface Science Advances, 2022

Material deterioration due to erosion and oxidation in high-temperature environments is a major c... more Material 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 Al 2 O 3 and WC-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/Al 2 O 3, NiCrSiB/n-Al 2 O 3 and NiCrSiB/WC-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 Al 2 O 3 outperformed all the other coatings in terms of oxidation resistance. When it comes to erosion resistance, NiCrSiB/WC-Co was found to demonstrate the highest performance.

Sustainability, 2021

Significant research efforts are directed towards finding new ways to reduce the cost, increase e... more Significant research efforts are directed towards finding new ways to reduce the cost, increase efficiency, and decrease the environmental impact of power-generation systems. The poly-generation concept is a promising strategy that enables the development of a sustainable power system. Over the past few years, the Proton Exchange Membrane Fuel Cell-based Poly-Generation Systems (PEMFC-PGSs) have received accelerated developments due to the low-temperature operation, high efficiency, and low environmental impact. This paper provides a comprehensive review of the main PEMFC-PGSs, including Combined Heat and Power (CHP) co-generation systems, Combined Cooling and Power (CCP) co-generation systems, Combined Cooling, Heat, and Power (CCHP) tri-generation systems, and Combined Water and Power (CWP) co-generation systems. First, the main technologies used in PEMFC-PGSs, such as those related to hydrogen production, energy storage, and Waste Heat Recovery (WHR), etc., are detailed. Then, th...

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00092-9 The accepted version of the publication may differ from the final published version.Metamaterials are artificial lattice structures or man-made cellular materials with unique mechanical, thermal, optical, and electromagnetic properties enabling their adoption for a wide range of engineering applications. The macroscopic performance of such metamaterials is dominated by the geometrical configuration of their respective unit cell which is normally engineered at microscale or nanoscale. These novel materials have attracted increased research interests as they offer a set of characteristics and functionalities that cannot normally be realized in conventional materials. High strength-to-density ratio and excellent energy absorption capabilities are among the properties exhibited by these materials making them ideal candidates for crashworthiness applications in automotive, aerospace, and defense engineering sectors. This article aims to review the recent developments concerning the energy absorption and impact responses of the metamaterials. An overview of the mechanical properties and manufacturing techniques of metamaterials is first introduced and then the recent studies on the energy absorption performance of metamaterials under dynamic and quasi-static loading are highlighted

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering on 01/06/2021, available online: https://doi.org/10.1016/B978-0-12-815732-9.00116-9 The accepted version of the publication may differ from the final published version.The behavior of matter at the nanoscale alters material properties in comparison to their bulk counterparts. Overall, materials at the nano-range demonstrate modified physical behaviors that offer favorable mechanical, thermodynamic, magnetic, optical, and biomedical properties for a range of applications. As such nanomaterials have their prominence in most scientific domains due to their ability to generate varied responses suitable for specific requirements. However, the implementation of nanomaterials in each situation requires a detailed understanding of the chemical and physical properties of the base materials, control parameters, and methods of fabrication. This paper introduces nanomaterials, their classification and measurement techniques followed by synthesis methods, common properties, applications, and prospects.Published versio

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published byElsevier in Reference Module in Material... more This is an accepted manuscript of an article published byElsevier in Reference Module in Materials Science and Materials Engineering on 14/12/2020, available online: https://doi.org/10.1016/B978-0-12-815732-9.00061-9 The accepted version of the publication may differ from the final published versionHydrogen continues to receive increased attention as the most promising energy carrier enabling sustainable and eco-friendly energy systems. Despite the various advantages of hydrogen fuel, storing hydrogen in a light-weight and compact form is the barrier towards the commercialization of the hydrogen technologies. Thus, the availability of a reliable, inexpensive, safe and efficient hydrogen storage technology is crucial to support and foster the transition to a hydrogen-powered world. Among the possible hydrogen storage solutions, storing hydrogen in the solid-state, such as metal hydrides, is the safest and most attractive method for on-board hydrogen storage. The metal hydrides can release highly pure hydrogen, via a low-pressure endothermic process, suitable to be used directly in the hydrogen fuel cell devices. This article presents an overview of using Mg and Mg2Ni-based alloys for solid-state hydrogen storage. A review of the hydrogen storage technologies is presented first and then the most recent developments on Mg and Mg2Ni-based hydrogen storage materials are highlighted.Published versio

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of a chapter published by Elsevier in Reference Module in Material... more This is an accepted manuscript of a chapter published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00127-3 The accepted version of the publication may differ from the final published version.

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00091-7 The accepted version of the publication may differ from the final published version.Acoustic metamaterials offer a new paradigm for the control and manipulation of sound waves that are often unachievable through conventional materials. The potential this offers to the field of sound absorption, insulation, cloaking, and imaging are remarkable. Acoustic metamaterials also allow material constructs to be tuned both actively and passively for reconfigurable material that offers unprecedented wave manipulation. Challenges remain, in simplifying, identifying scaling techniques and deriving design guidelines for the manufacture of large-scale acoustic metamaterials to transform laboratory prototypes to useful devices. However, research in this area is rapidly evolving with the necessary building blocks that can be additively manufactured or assembled to form metamaterials. In this regard, the article provides a general introduction into acoustic metamaterials followed by their qualifiers. The focus is placed on summarizing the advances that are happening in the field of acoustic metamaterials classified based on potential application. In doing so key design approaches and resulting properties of acoustic metamaterials are discussed in relation to their most recent advancements.Published versio

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00090-5 The accepted version of the publication may differ from the final published version.The term “metamaterials” refers to artificial constructs whose characteristics are determined by the collective manifestations of local units. When such constructs are designed for acoustic wave manipulation, they are referred to as acoustic metamaterials. Acoustic metamaterials allow controlled wave propagation that is often inconceivable through chemically developed bulk materials. This means that the wave propagation in acoustic metamaterials goes beyond the mass-density characteristics of the material resulting in targeted acoustic outcomes. The unique characteristics of acoustic metamaterials have opened a new direction in the development of effective solutions for a range of applications, including but not limited to low-frequency sound insulation, acoustic cloaking, sound focusing, biomedical acoustics, and passive destructive interference. The overall characteristic of an acoustic metamaterial depends on the type of sound manipulation being targeted. This article introduces the characteristics associated with some of the most promising acoustic metamaterials from passive to active. An effort is placed to highlighting both the underlying principles and the physical prototypes that were evaluated.Published versio

Encyclopedia of Smart Materials, 2022

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2021

On-demand additive manufacturing (three-dimensional printing) offers great potential for the deve... more On-demand additive manufacturing (three-dimensional printing) offers great potential for the development of functional materials for the next generation of energy-efficient devices. In particular, novel materials suitable for efficient dissipation of localised heat fluxes and non-uniform thermal loads with superior mechanical performance are critical for the accelerated development of future automotive, aerospace and renewable energy technologies. In this regard, this study reports the laser powder bed fusion processing of high purity (>99%) copper (Cu), silver (Ag) and novel copper–silver (CuAg) alloys ready for on-demand additive manufacturing. The processed materials were experimentally analysed for their relative density, mechanical and thermal performance using X-ray computed tomography, destructive tensile testing and laser flash apparatus, respectively. It was found that while Ag featured higher failure strains, Cu in comparison showed a 109%, 17% and 59% improvement in yi...

Reference Module in Materials Science and Materials Engineering, 2019

Cellular foams are a modern class of materials with unique mechanical properties that have wide r... more Cellular foams are a modern class of materials with unique mechanical properties that have wide ranging engineering applications, in the areas of biomedical, acoustic and thermal insulation, and crashworthiness. Recently, foam materials have received increased attention for vehicle crashworthiness due to their lightweight and excellent energy absorption capabilities that allow significant weight reduction without compromising structural safety aspects. Accordingly, this paper reviews the crush and energy absorption behaviour of foam-filled structures that can be used for crashworthy design in transport engineering. In addition, the mechanical and dynamic properties of cellular material and their role on the crashworthiness performance of filled structure are discussed. Particularly, the influences of foam density and interactions, between the foam and the tubes, on the deformation mode of the filled structures are clarified. The advantages offered by the innovative foam material, which contains a density gradient, on the crashworthiness behaviour are also highlighted. Also, a brief summary of optimisation studies involving the use of foam-filled structures are presented. It was found that the cellular materials improve the crashworthiness performance when they are used as filler material in thin-walled energy absorbers due to their capability of altering the deformation mode to a more favourable one.

Materials

Journal of Hydrodynamics, 2021

Applied Surface Science Advances, 2022

Sustainability, 2021

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering on 01/06/2021, available online: https://doi.org/10.1016/B978-0-12-815732-9.00116-9 The accepted version of the publication may differ from the final published version.The behavior of matter at the nanoscale alters material properties in comparison to their bulk counterparts. Overall, materials at the nano-range demonstrate modified physical behaviors that offer favorable mechanical, thermodynamic, magnetic, optical, and biomedical properties for a range of applications. As such nanomaterials have their prominence in most scientific domains due to their ability to generate varied responses suitable for specific requirements. However, the implementation of nanomaterials in each situation requires a detailed understanding of the chemical and physical properties of the base materials, control parameters, and methods of fabrication. This paper introduces nanomaterials, their classification and measurement techniques followed by synthesis methods, common properties, applications, and prospects.Published versio

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00091-7 The accepted version of the publication may differ from the final published version.Acoustic metamaterials offer a new paradigm for the control and manipulation of sound waves that are often unachievable through conventional materials. The potential this offers to the field of sound absorption, insulation, cloaking, and imaging are remarkable. Acoustic metamaterials also allow material constructs to be tuned both actively and passively for reconfigurable material that offers unprecedented wave manipulation. Challenges remain, in simplifying, identifying scaling techniques and deriving design guidelines for the manufacture of large-scale acoustic metamaterials to transform laboratory prototypes to useful devices. However, research in this area is rapidly evolving with the necessary building blocks that can be additively manufactured or assembled to form metamaterials. In this regard, the article provides a general introduction into acoustic metamaterials followed by their qualifiers. The focus is placed on summarizing the advances that are happening in the field of acoustic metamaterials classified based on potential application. In doing so key design approaches and resulting properties of acoustic metamaterials are discussed in relation to their most recent advancements.Published versio

Encyclopedia of Smart Materials, 2022

This is an accepted manuscript of an article published by Elsevier in Reference Module in Materia... more This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering, available online: https://doi.org/10.1016/B978-0-12-815732-9.00090-5 The accepted version of the publication may differ from the final published version.The term “metamaterials” refers to artificial constructs whose characteristics are determined by the collective manifestations of local units. When such constructs are designed for acoustic wave manipulation, they are referred to as acoustic metamaterials. Acoustic metamaterials allow controlled wave propagation that is often inconceivable through chemically developed bulk materials. This means that the wave propagation in acoustic metamaterials goes beyond the mass-density characteristics of the material resulting in targeted acoustic outcomes. The unique characteristics of acoustic metamaterials have opened a new direction in the development of effective solutions for a range of applications, including but not limited to low-frequency sound insulation, acoustic cloaking, sound focusing, biomedical acoustics, and passive destructive interference. The overall characteristic of an acoustic metamaterial depends on the type of sound manipulation being targeted. This article introduces the characteristics associated with some of the most promising acoustic metamaterials from passive to active. An effort is placed to highlighting both the underlying principles and the physical prototypes that were evaluated.Published versio

Encyclopedia of Smart Materials, 2022

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2021

Reference Module in Materials Science and Materials Engineering, 2019