Browsing by Author "Chen, Yong Kang"

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    An Analytical Model for the Identification of the Threshold of Stress Intensity Factor Range for Crack Growth
    (Hindawi, 2017-01-18) Grasso, Marzio; De Iorio, Antonio; Xu, Yigeng; Haritos, George; Mohin, M.; Chen, Yong Kang
    The value of the stress intensity factor (SIF) range threshold ( ) for fatigue crack growth (FCG) depends highly on its experimental identification. The identification and application of are not well established as its determination depends on various factors including experimental, numerical or analytical techniques used. A new analytical model which can fit the raw FCG experimental data is proposed. The analytical model proposed is suitable to fit with a high accuracy the experimental data and capable to estimate the threshold SIF range. The comparison between the threshold SIF range identified with the model proposed and those found in literature is also discussed. The identified is found to be quite accurate and consistent when compared to the literature with a maximum deviation of 5.61%. The accuracy with which the analytical model is able to fit the raw data is also briefly discussed.
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    Design and manufacturing challenges of a microturbine wheel
    (European Conference on Turbomachinery (ETC), 2023-04-28) Hosseini, Seyed Vahid; Gamil, Abdelaziz; Soodani, Sara; Nikolaidis, Theoklis; Madani, Seyed Hossein; Chen, Yong Kang; Chizari, Mahmoud
    Micro gas turbine (MGT) is a core technology in many hybrid and integrated power systems to address the low-emission future aviation and decentralisation of energy generation. To achieve a high power-to-weight ratio as well as lowering the required maintenance, a new compact configuration with an air-bearing compartment was developed to build a 2 kW micro gas turbine. Designing a turbine wheel faced a multidisciplinary problem with many inputs and constraints in aerodynamic, heat transfer, strength, and manifesting aspects. To meet all requirements of these aspects, a design procedure is proposed in this paper. Since the manufacturing process affects the performance and life of the system, several processes, including casting, additive manufacturing (AM) and machining of the turbine wheel with different materials, were carried out, and the structural strength and performance of the components were investigated in this study. The prototype was tested experimentally to prove its performance and validate the concept. The cast wheel demonstrated both the required performance of 2 kW power output of the MGT in turbine inlet temperature of 1200 K and rotational speed of 170 krpm. However, the machined and additive manufactured samples for low-temperature/low-speed off-design conditions did not withstand structurally and called for a re-design or change in conditions.
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    The EUCAMS gear partnership - a model of industry/academic collaboration
    (British Institute of Non-Destructive Testing, 2011-12-31) Starr, Andrew; Khan, Muhammad; Allen, Brian; Marshall, Mick; Phang, Albert; Badi, Nuri; Chen, Yong Kang; Edwards, Rodger; Sinha, Jyoti; Rzeszucinski, Pawel; Jones, Rhys; Mao, Ken; Shepherd, Duncan; Curran, Alan
    Challenges in maintenance systems can pose multi-faceted problems, which are difficult to resolve alone. Over a four year period, a partnership evolved a vision for tackling the understanding of fundamentally difficult mechanical failures and their detection, with potential for practical exploitation of the solutions. The partnership assembled a team of researchers and far-sighted project management, to undertake a study of gearbox failures, including finite element modelling, gear testing, and signal analysis. The partnership trained a series of doctoral and postdoctoral staff in running an integrated project, coping with changes in staffing and locations. The final stages of the work will validate the models and signal processing.
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    Low-velocity impact behaviour of woven laminate plates with fire retardant resin
    (Elsevier, 2019-04-27) Grasso, Marzio; Xu, Yigeng; Ramji, Amit; Zhou, Gang; Chrysanthou, Andreas; Haritos, George; Chen, Yong Kang
    The understanding of the damage mechanisms for woven laminate plates under low-velocity impact is challenging as the damage mechanisms at the interface of adjacent layers are dominated by the fibre architecture. This work presents an experimental investigation of the behaviour of woven glass and carbon fibre composite laminates in a matrix of fire retardant resin under low-velocity impact. The performance is evaluated in terms of damage mechanisms and force time history curves. Six impact energy levels were used to test standard plates to identify the type of damage observed at various energy levels. Scanning electron microscopy (SEM) along with C-scans were used to characterise the damage. It has been observed that in woven composites, the damage occurs mostly between the fibre bundles and matrix. As the impact energy increases, the failure involves extended matrix cracking and fibre fracture. Moreover, due to the fibre architecture, both the contact forces between bundles of fibres and stretching of the bundles are responsible for the dominant matrix cracking damage mode observed at the low-impact energy level. As the impact energy increases, the damage also increases resulting in fibre fracture. The experimental evidence collected during this investigation shows that for both the carbon fibre and the glass fibre woven laminates the low-velocity impact behaviour is characterised by extended fibre fracture without a noticeable sudden load drop.