Mechanical Engineering
http://hdl.handle.net/10034/623015
2024-03-28T12:20:09ZComputational and Experimental Study on the Resistance Welding Process of a Glass Fibre-Reinforced Epoxy-Based Composite with Thermoplastic Interlayer Adherent
http://hdl.handle.net/10034/628412
Computational and Experimental Study on the Resistance Welding Process of a Glass Fibre-Reinforced Epoxy-Based Composite with Thermoplastic Interlayer Adherent
Liang, Yunhao; Shi, Yu
In this work, resistance welding of a glass fibre-reinforced epoxy composite (GFRC) was studied with numerical optimisation and experimental validation. A steel mesh and polymethyl methacrylate (PMMA) films were used as the heating element and adherent interlayers, respectively. A transient heat transfer module was implemented to conduct the parametric optimisation study, with variables of electricity power, clamping distance and weld time. The optimal welding condition was then confirmed as 20 W, 0.4 mm and 30 s, with the melting degree of 95.2 %. A thermal meter and a thermal camera validated the simulated temperature results. Welding quality was experimentally characterized by single lap shear tests and scanning electron microscopy (SEM). The highest lap shear strength of 3.8 ± 0.3 MPa was captured on the specimen welded with the optimised condition. This was 76 % that of the benchmark made with adhesive bonding method but it was over 200 times faster.
2024-01-11T00:00:00ZStudent perceptions of remote learning transitions in engineering disciplines during the COVID-19 pandemic: a cross-national study
http://hdl.handle.net/10034/628318
Student perceptions of remote learning transitions in engineering disciplines during the COVID-19 pandemic: a cross-national study
Behera, Amar Kumar; de Sousa, Ricardo Alves; Oleksik, Valentin; Dong, Jingyan; Fritzen, Daniel
This study captures student perceptions of the effectiveness of remote learning and assessment in two associated engineering disciplines, mechanical and industrial, during the COVID-19 pandemic in a cross-national study. A structured questionnaire with 24 items on a 5-point Likert scale was used. Parallel and exploratory factor analyses identified three primary subscales. The links between student perceptions and assessment outcomes were also studied. There was a clear preference for face-to-face teaching, with the highest for laboratories. Remote live lectures were preferred over recorded. Although students found the switch to remote learning helpful, group work and communication were highlighted as concern areas. Mean scores on subscales indicate a low preference for remote learning (2.23), modest delivery effectiveness (3.05) and effective digital delivery tools (3.61). Gender effects were found significant on all subscales, along with significant interactions with university and year-group. Preference for remote delivery of design-based modules was significantly higher than others.
2022-06-06T00:00:00ZFabrication of superamphiphobic surface with re-entrant structures via self-assembly colloidal template-assisted electrochemical deposition
http://hdl.handle.net/10034/627864
Fabrication of superamphiphobic surface with re-entrant structures via self-assembly colloidal template-assisted electrochemical deposition
Zhang, Haoran; Xue, Pengbo; Wang, Menglin; Wang, Jinfeng; Shi, Yu; Pan, Lei
Superamphiphobic surfaces with re-entrant structures have attracted widespread attention due to their superior water and oil resistance. However, current methods for fabricating superamphiphobic surfaces mostly rely on expensive equipment and cumbersome processes. This paper represents a facile and controlled preparation method for superamphiphobic surfaces with zinc oxide (ZnO) re-entrant structures using self-assembled polystyrene (PS) monolayer colloidal crystals (MCCs) as templates to assist electrochemical deposition of ZnO film. The prepared surface shows contact angles (CAs) larger than 150° and sliding angles smaller than 10° for water, glycerol, ethylene glycol (EG), and olive oil. The morphology and size of the re-entrant structures were modulated by the deposition potential and time, and the mechanism of the influence of the structures on the wetting properties was investigated. This superamphiphobic surface with re-entrant structures can be used as a surface-enhanced Raman spectroscopy (SERS) substrate for molecular detection with a detection limit of 10−10 M for rhodamine (R6G), benefiting from the enrichment effect of the superamphiphobic surface and the Schottky barrier at the Ag/ZnO contact interface. We hope that this preparation method for superamphiphobic surface has broad application prospects in the fields of self-cleaning, anti-icing, anti-fog, corrosion resistance, microfluidics, photocatalysis and fluid drag reduction.
This article is not available on ChesterRep
2023-06-16T00:00:00ZEnergy harvesting using a magnetostrictive transducer based on switching control
http://hdl.handle.net/10034/627665
Energy harvesting using a magnetostrictive transducer based on switching control
Li, An; Goto, Keiju; Kobayashi, Yuusuke; Hara, Yushin; Shi, Yu; Jia, Yu; Soutis, Constantinos; Kurita, Hiroki; Kurita, Fumio; Otsuka, Keisuke; Makihara, Kanjuro
In this works we propose a switching control energy harvesting method using magnetostrictive materials. By combining a magnetostrictive material, an electric circuit, and an electronic switch, large-scale kinetic to electrical energy conversion can be achieved. The magnetostrictive material, magnet bias, and coils constitute an energy transducer, called a magnetostrictive transducer. The electronic switch strategically controls the switching of the circuit state according to an input switching signal. Using numerical simulations, we optimised the parameters and validated the harvesting performance with experimental measurements using a 3.75 m vibrated cantilever truss structure. In 20.0 s, the proposed method achieved an electrical energy of approximately 45 μJ, which is seven times more than that of the conventional passive method.
2023-03-14T00:00:00Z