Now showing 1 - 5 of 55
- ItemModelling of a tubular kirigami (RC-kiri) with outside lamina emergent torsional joints(Springer Nature Ltd., 2023-04-16) Ye, Siyuan; Zhao, Pengyuan; Li, Shiyao; Kavousi, Fatemeh; Hao, GuangboThis paper applies the traditional kirigami technique to the non-rigid-foldable tubular origami, which provides a new method to convert the non-rigid foldability. Tubular Yoshimura and Kresling origami, as two typical non-rigid-foldable structures, are applied with the kirigami technique and presented. A radially closable origami (RC-ori) becomes a rigid-foldable kirigami (RC-kiri) when cutting the connected edges of every folding unit. The creases of RC-kiri are applied with outside LET joints, and the simulated model is constructed and analysed by Abaqus. The force-displacement relationship is obtained which shows two stages divided by the critical instability point. The FEA results are compared with the theoretical results, and its potential sources of errors are analysed. A physical model is made by 3D printing. The verification methods including dihedral angles, diameter-displacement curves, and force-displacement curves in outward folding configuration. Our study builds a bridge between origami and kirigami and expands the application of LET joints to the fabrication of tubular kirigami.
- ItemUsing model selection and reduction to develop an empirical model to predict energy consumption of a CNC machine(Springer Nature Switzerland AG, 2022-10-17) Morris, Liam; Clancy, Rose; Hryshchenko, Andriy; O’Sullivan, Dominic; Bruton, Ken; Margaria, Tiziana; Steffen, Bernhard; Horizon 2020With an ever growing need to reduce energy consumption in the manufacturing industry, process users need to become more aware on how production impacts energy consumption. Computer numerically controlled (CNC) machining tools are a common manufacturing apparatus, and they are known to be energy inefficient. This paper describes the development of an empirical energy consumption model of a CNC with the aim of predicting energy consumption based on the number of parts processed by the machine. The model can then be deployed as part of a decision support (DS) platform, aiding process users to reduce consumption and minimise waste. In using the Calibrated Model Method, the data undergoes initial preparation followed by exploratory data analysis and subsequent model development via iteration. During this analysis, relationships between parameters are explored to find which have the most significant on energy consumption. A training set of 191 datapoints yielded a linear correlation coefficient of 0.95, between the power consumption and total units produced. RMSE, MAPE and MBE validation test yielded results of 0.198, 6.4% and 2.66% respectively.
- ItemThe effect of pore water pressure on structural performance of CERN concrete-lined tunnel(Civil Engineering Research Association of Ireland, 2020) Xiao, Zhipeng; Osborne, John Andrew; Perez-Duenas, Eliseo; Li, Zili; Ruane, Kieran; Jaksic, Vesna; Horizon 2020The European Centre for Nuclear research (CERN) operates the most powerful circular particle accelerator in a large-scale underground tunnel network of over 70 km. Even over four decades after construction, substantial cracks, water infiltration and structural deformation have still been developing with time based upon field observation and measurements. In particular, recent blockage of tunnel drainage system alters the hydraulic boundary condition and results in the development of pore-water pressure around the tunnel circumference, which in turn accelerates the tunnel deterioration and leakage. In this study, the development of pore water pressure and its effect on tunnel lining are investigated using 3D hydro-mechanical coupled finite element modelling. In the numerical simulation, particular emphasis is placed on the change of lining permeability and the drainage system with time. Results show that the pore water pressure on tunnel lining is significantly affected by the change of hydraulic condition, and consequently exacerbates the tunnel structural performance in the long term.
- ItemStructure design and assessment of a floating foundation for offshore wind turbines(American Society of Mechanical Engineers (ASME), 2019-11-03) Ye, Q.; Cheng, S.; Kim, B.; Collins, K.; Iglesias, GregorioThis paper summarizes the assessment of the structural analysis and design of a floating foundation for offshore floating wind turbine (FWT) based on DNVGL standard and Eurocode in terms of economy and reliability. The wind loads are calculated using empirical equations. The wave loads are obtained and verified using various methods including hand calculation, AQWA and Flow-3D. It is found that the shell thickness could be reduced significantly by introducing the stiffeners (stringer or ring), which can decrease the weight of the hull and lower the cost. While DNVGL and Eurocode yield similar design solutions if using plane shell structures, Eurocode significantly underestimates the buckling resistance of stiffened cylindrical shells.
- ItemAutomatic UAV inspection of tunnel infrastructure in GPS-denied underground environment(Springer Nature Switzerland AG, 2022-06-16) Zhang, Ran; Ouyang, Aohui; Li, ZiliIn the Architecture, Engineering and Construction (AEC) industry, unmanned aerial vehicles (UAV) has been widely acknowledged as a promising tool to perform adaptive structural health monitoring automatically. However, there still remains some challenges for drones to collect image data of underground structures, primarily due to low light and no GPS conditions. In order to facilitate data acquisition, this article developed a mobile software development kit (MSDK) for drone using visual positioning and predefined controlling code, which enabled the drone to automatically fly along a designated sinusoidal route, whilst continuously taking videos and images of the tunnel surface. The developed MSDK was able to adjust the drone parameters (e.g., overlapping rate, inspection range, heading, flight direction between frames of the video) for different underground infrastructure conditions. Furthermore, a field test is conducted in an abandoned windless tunnel near Cork (Goggins Hill Tunnel) to test its feasibility. Results show that the 40-m difference between the designated routine and actual routine was 1.9%, and the collected data processed by Pix4Dmapper could reconstruct the complete tunnel scene and surface details. The navigation method proposed in this paper allows UAVs to perform automatic inspection without GPS, and the collected image data is used to build a tunnel panorama view.