ORCID Profile
0000-0001-7518-1414
Current Organisation
Nanyang Technological University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2TA00351A
Publisher: Informa UK Limited
Date: 24-05-2018
Publisher: Springer Science and Business Media LLC
Date: 19-03-2015
Publisher: Wiley
Date: 16-11-2017
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 06-2016
Publisher: SAGE Publications
Date: 14-02-2017
Abstract: A scaled, 7.5-mm thick, unidirectional glass/epoxy wind turbine spar cap cured in a vacuum-assisted oven was found to have attained non-uniform thickness along its length. Edge deformations were severe, leading to noticeable edge curvature even at the vacuum pressure. These unforeseen discrepancies could only be predicted and/or dealt beforehand through a process simulation that integrates the complete processing physics. A fully coupled numerical simulation of composites manufacturing was established and implemented for a portion of a spar cap in multiphysics finite element software. Phenomena such as resin flow-induced compaction and cure-induced deformation were captured. The simulation results indicated that even though the distorted edge of the laminate is trimmed off, there will still be some curvature left within the part. It was noted that simulating percolation flow of resin alone leads to less accurate deformation predictions. Therefore, a method to include shear flow-induced deformation of the resin-saturated fiber beds were proposed and implemented. Such a fully coupled and integrated procedure is useful for optimizing process parameters to achieve intended final part with accurate dimensions and minimal manufacturing-induced defects or deformities.
Publisher: Elsevier BV
Date: 11-2010
Publisher: Elsevier BV
Date: 07-2009
Publisher: Elsevier BV
Date: 08-2011
Publisher: Elsevier BV
Date: 12-2016
Publisher: Maney Publishing
Date: 03-05-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CP03243A
Abstract: Ice nucleation tends to occur at the three-phase contact line instead of on the liquid/solid contact interface.
Publisher: Wiley
Date: 30-07-2018
Publisher: American Chemical Society (ACS)
Date: 19-11-2014
DOI: 10.1021/AM504348X
Abstract: Sol-gel coatings with different roughness and surface energy were prepared on glass substrates. Methyl triethoxysilane (MTEOS), 3-Glycidyloxypropyl trimethoxysilane (GLYMO) and fluoroalkylsilane (FAS) were used to obtain a mechanically robust icephobic coating. Different amount of hydrophobic silica nano particles was added as fillers to introduce different roughness and surface energy to the coatings. The microstructure, roughness, and surface energy, together with elemental information and surface chemical state, were investigated at room temperature. The contact angle and sliding angle were measured at different temperatures to correlate the wetting behavior at low temperature with the anti-icing performance. The ice adhesion shear strength was measured inside an ice chamber using a self-designed tester. The factors influencing the ice adhesion were discussed, and the optimum anti-icing performance found in the series of coatings. It was found that lower surface energy leads to lower ice adhesion regardless of the roughness, while the roughness plays a more complicated role. The wetting behavior of the droplet on surface changes as temperature decreases. The anti-icing performance is closely related to the antiwetting property of the surfaces at subzero temperatures.
Publisher: Elsevier BV
Date: 03-2013
Publisher: American Chemical Society (ACS)
Date: 31-12-2020
Publisher: MDPI AG
Date: 10-07-2017
DOI: 10.3390/MA10070776
Publisher: SAGE Publications
Date: 18-03-2014
Abstract: This article deals with the computation of effective elastic properties of braided textile composites assisted by finite element analysis. In this approach, dynamic representative unit cells are first constructed to model typical geometry of braided textile preform. After establishing the elastic properties of braiding yarns, the effective Young’s moduli, shear moduli and Poisson’s ratios corresponding to varying braiding angles are obtained by analysing these geometric models of preform with the help of the commercial finite element analysis code Abaqus. Effects of fibre volume fraction on the elastic properties of both biaxial and triaxial composite unit cells are also examined. Finally, the bending behaviour of a simply supported beam with braided composite skin is evaluated via the finite element analysis assisted multi-scale modelling, which is further verified experimentally. The predicted results were compared favourably with the experiment, backing the accuracy of the proposed modelling approach.
Publisher: AIP Publishing
Date: 12-2010
DOI: 10.1063/1.3514005
Abstract: A micromechanism of thermosonic gold wire bonding was elaborated by examining its interfacial characteristics as a result of the bonding process, including the fragmentation of the native aluminum oxide layer on Al pads, and formation of initial intermetallic compounds (IMCs). It is found that the existence of an approximately 5 nm thick native oxide layer on original Al pads has a significant effect on the bonding, and the nucleation of IMCs during the bonding process must overcome this relatively inert thin film. Bonding strength was fundamentally determined by the degree of fragmentation of the oxide films, through which the formation of IMCs can be initiated due to the direct contact of the metal surfaces to be bonded. The extent of fracture the oxide layer was strongly influenced by the level of ultrasonic power, as at its high level alumina fragmentation becomes pervasive resulting in contiguous alloy interfaces and robust bonds. The IMCs formed at the interfaces were identified as Al4Al and AuAl2 with a thickness of 150–300 nm. The formation mechanism of such IMCs was explained by the effective heat of formation theory.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 10-2011
Publisher: American Physical Society (APS)
Date: 02-03-2007
Publisher: Trans Tech Publications, Ltd.
Date: 08-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.740.698
Abstract: Thick laminated composites are manufactured commonly by vacuum bagging of fiber-resin mix or prepregs on a suitable mould and, subsequently curing the lay-up at high temperature and pressure in an either autoclave or oven. At these pressures and temperatures, excess resin bleeds out of the lay-up during the initial stages of the curing. The amount of resin bleed is also a function of the bleeder parameters. Bleeder is a porous fibrous media that is laid around stacked lay-up to provide pathway for volatiles as well as absorb and hold the excess resin. Thicker or highly porous bleeders generally absorb higher amount of resin resulting in a resin starved laminate whereas very thin or denser bleeder leads to resin-rich areas within the laminate. It is thus important to select optimum bleeder parameters in order to achieve a desired resin volume fraction and its uniformity in a composite laminate upon curing. This paper details the simulation of the manufacturing of a thick laminated composite, where a significant amount resin is likely to flow out of a curing lay-up, leading to an optimization of bleeder parameters. A coupled, transient FE analysis is conducted that involves not only the heat transfer, resin flow and cure reaction kinetics simulation but also the simulation of the compaction of the wet laminate and the bleeder layers until the laminate is fully cured. Details of an experiment conducted to find compression characteristics of bleeder of varying thickness and the number of layers and related data that was used in the FE analysis are discussed in this paper. It is found that bleeder thickness significantly affects the amount of resin bleeding out from the curing laminate. As a result, the resin volume fraction of the laminate is affected. Case studies carried out to highlight the optimum bleeder thickness for a lay-up, and the method used to decide the thickness and the number of bleeder layers, are presented.
Publisher: SAGE Publications
Date: 28-07-2016
Abstract: A novel technique to predict the manufacturing process-induced distortions and deformations in thick unidirectional carbon fiber reinforced plastics laminates is detailed in this article. An integrated numerical model is developed to account for non-isothermal resin flow, related compaction, transient resin cure, and resin shrinkage effects to predict the final shape of the autoclave cured thick prepreg laminate. The associated physics are mathematically coupled to solve for the process variables interactively. The results illustrate reduction in the thickness of the laminate prior to the start of curing when initial fiber volume fractions are pre-set. This confirms that the initial transverse deformation of B-stage prepreg is due to the applied vacuum and/or pressure. Once curing initiates, deformation of the laminate due to compaction increases, proportionally, with the increase in fiber volume fraction. Furthermore, the thermo-chemical residual strains contribute to additional compaction. The final distorted shape observed in simulation of the originally flat laminate matches with the shape of the fabricated laminate with 6.6 mm thickness. A solution to minimize the distortion is discussed in detail. This procedure is extended to simulate a curved laminate’s processing where, the shear moduli were observed to influence the final shape of the laminate. The findings are presented and deliberated in this article.
Publisher: Springer Science and Business Media LLC
Date: 22-10-2016
Publisher: Elsevier BV
Date: 12-2011
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Zhong Chen.