Mechanical Engineering: Research@ Brunel

Research published by Brunel staff

Below are recent articles (co-)authored by Brunel academic staff. Please click the title of the article to access the full-text.

• Enhancing biodegradable smart food packaging: Fungal-synthesized nanoparticles for stabilizing biopolymers
  Rami, M. R. et al
  Heliyon, Vol 10, No 18, Art No. e37692 (Sep 2024)
  The increasing global concern over environmental plastic waste has propelled the progress of biodegradable supplies for food packaging. Biopolymer-based packaging is undergoing modifications to enhance its mechanical properties, aligning with the requirements of smart food packaging. Polymer nanocomposites, incorporating reinforcements such as fibers, platelets, and nanoparticles, demonstrate significantly improved mechanical, thermal, optical, and physicochemical characteristics. Fungi, in particular, have garnered significant interest for producing metallic nanoparticles, offering advantages such as easy scaling up, streamlined downstream handling, economic feasibility, and a large surface area. This review provides an overview of nano-additives utilized in biopackaging, followed by an exploration of the recent advancements in using microbial-resistant metal nanoparticles for food packaging. The mycofabrication process, involving fungi in the extracellular or intracellular synthesis of metal nanoparticles, is introduced. Fungal functionalized nanostructures represent a promising avenue for application across various stages of food processing, packaging, and safety. The integration of fungal-derived nanostructures into food packaging materials presents a sustainable and effective approach to combatting microbial contamination." By harnessing fungal biomass, this research contributes to the development of economical and environmentally friendly methods for enhancing food packaging functionality. The findings underscore the promising role of fungal-based nanotechnologies in advancing the field of active food packaging, addressing both safety and sustainability concerns. The study concludes with an investigation into potential fungal isolates for nanoparticle biosynthesis, highlighting their relevance and potential in advancing sustainable and efficient packaging solutions.

• A new hyper-elastic law for single yield surface constitutive models for clays
  Argani, L. P. et al
  Computers and geotechnics, Vol 176, Art No. 106707 (Dec 2024)
  The elasticity law is a great challenge in soils, due to the well-known non-linear, anisotropic, pressure-dependent soil response even at negligibly small strains. A new hyper-elastic formulation is proposed, based on a polynomial expression (including a fabric tensor defining the elastic anisotropy) with two branches, one for the negligibly small stresses, ensuring good convergence properties at low confining pressure, and one for the soil response at intermediate strains, corresponding to stress states inside a single large-sized, yield surface defining the occurrence of large irreversible strain. Typical numerical simulations are discussed for isotropic and oedometric compression and swelling tests, and for undrained triaxial compression tests. The results are compared with those obtained with similar hyper-elastic models proposed in the literature. A comparison with experimental oedometric and drained and undrained triaxial tests on undisturbed samples of London clay is provided, revealing that the proposed model has great flexibility in selecting both the shear stiffness and the evolution of elastic anisotropy, which can be chosen independently, thus providing a general applicability. For instance, the great flexibility of the proposed hyper-elastic formulation can be exploited to model the non-linear swelling curves typically observed in oedometric swelling tests of structured clays or active clays.

• Modelling and Characterisation of Orthotropic Damage in Aluminium Alloy 2024
  Djordjevic, N. et al
  Materials, Vol 17 No 17 Art No. 4281 (Sep 2024)
  The aim of the work presented in this paper was development of a thermodynamically consistent constitutive model for orthotopic metals and determination of its parameters based on standard characterisation methods used in the aerospace industry. The model was derived with additive decomposition of the strain tensor and consisted of an elastic part, derived from Helmholtz free energy, Hill's thermodynamic potential, which controls evolution of plastic deformation, and damage orthotopic potential, which controls evolution of damage in material. Damage effects were incorporated using the continuum damage mechanics approach, with the effective stress and energy equivalence principle. Material characterisation and derivation of model parameters was conducted with standard specimens with a uniform cross-section, although a number of tests with non-uniform cross-sections were also conducted here. The tests were designed to assess the extent of damage in material over a range of plastic deformation values, where displacement was measured locally using digital image correlation. The new model was implemented as a user material subroutine in Abaqus and verified and validated against the experimental results for aerospace-grade aluminium alloy 2024-T3. Verification was conducted in a series of single element tests, designed to separately validate elasticity, plasticity and damage-related parts of the model. Validation at this stage of the development was based on comparison of the numerical results with experimental data obtained in the quasistatic characterisation tests, which illustrated the ability of the modelling approach to predict experimentally observed behaviour. A validated user material subroutine allows for efficient simulation-led design improvements of aluminium components, such as stiffened panels and the other thin-wall structures used in the aerospace industry.

• A review of control strategies for proton exchange membrane (PEM) fuel cells and water electrolysers: From automation to autonomy
  Mao, J. et al
  Energy and AI, Vol 17, Art No. 100406 (Sep 2024)
  Proton exchange membrane (PEM) based electrochemical systems have the capability to operate in fuel cell (PEMFC) and water electrolyser (PEMWE) modes, enabling efficient hydrogen energy utilisation and green hydrogen production. In addition to the essential cell stacks, the system of PEMFC or PEMWE consists of four sub-systems for managing gas supply, power, thermal, and water, respectively. Due to the system's complexity, even a small fluctuation in a certain sub-system can result in an unexpected response, leading to a reduced performance and stability. To improve the system's robustness and responsiveness, considerable efforts have been dedicated to developing advanced control strategies. This paper comprehensively reviews various control strategies proposed in literature, revealing that traditional control methods are widely employed in PEMFC and PEMWE due to their simplicity, yet they suffer from limitations in accuracy. Conversely, advanced control methods offer high accuracy but are hindered by poor dynamic performance. This paper highlights the recent advancements in control strategies incorporating machine learning algorithms. Additionally, the paper provides a perspective on the future development of control strategies, suggesting that hybrid control methods should be used for future research to leverage the strength of both sides. Notably, it emphasises the role of artificial intelligence (AI) in advancing control strategies, demonstrating its significant potential in facilitating the transition from automation to autonomy.