Searched for: author%3A%22Liu%2C+D.%22
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Liu, D. (author), Virgolin, Marco (author), Alderliesten, T. (author), Bosman, P.A.N. (author)
Genetic programming (GP) is one of the best approaches today to discover symbolic regression models. To find models that trade off accuracy and complexity, the non-dominated sorting genetic algorithm II (NSGA-II) is widely used. Unfortunately, it has been shown that NSGA-II can be inefficient: in early generations, low-complexity models over...
conference paper 2022
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Zhang, J. (author), Zhebel, E.V. (author), van den Boom, S.J. (author), Liu, D. (author), Aragon, A.M. (author)
In this work, an object-oriented geometric engine is proposed to solve problems with discontinuities, for instance, material interfaces and cracks, by means of unfitted, immersed, or enriched finite element methods (FEMs). Both explicit and implicit representations, such as geometric entities and level sets, are introduced to describe...
journal article 2022
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Liu, D. (author), van den Boom, S.J. (author), Simone, A. (author), Aragon, A.M. (author)
We propose an enriched finite element formulation to address the computational modeling of contact problems and the coupling of non-conforming discretizations in the small deformation setting. The displacement field is augmented by enriched terms that are associated with generalized degrees of freedom collocated along non-conforming...
journal article 2022
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Ma, Lulu (author), Liu, Feng (author), Liu, D. (author), Liu, Y. (author)
The application of fiber-reinforced polymer (FRP) composites is gaining increasing popu-larity in impact-resistant devices, automotives, biomedical devices and aircraft structures due to their high strength-to-weight ratios and their potential for impact energy absorption. Impact-induced high loading rates can result in significant changes of...
review 2021
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Liu, D. (author), Song, X. (author), Deng, Fujin (author), Dong, J. (author)
High-Temperature superconducting (HTS) generators are being considered as a competitive candidate in large direct-drive (DD) wind turbines because of their features of being lightweight and compact. Normally a large air gap is inevitable in partially HTS generators, sacrificing the torque producing capability. In this paper, multi-phase...
journal article 2020
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Liu, D. (author), Yu, Wenwu (author), Baldi, S. (author), Cao, Jinde (author), Huang, Wei (author)
The work presented in this paper concerns a switching-based control formulation for multi-intersection and multiphase traffic light systems. A macroscopic traffic flow modeling approach is first presented, which is instrumental to the development of a model-based and switching-based optimization method for traffic signal operation, in the...
journal article 2020
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Liu, Nan (author), Liu, D. (author), Wang, Weifei (author), Hollmann, F. (author), Xu, Long (author), Ma, Yunjian (author), Yang, Bo (author), Bai, Weidong (author), Sun, Xiaotao (author), Wang, Yonghua (author)
α‐Linolenic acid‐rich diacylglycerol has been demonstrated with promising health promotion functions. This study examined the production, immobilization of lipase PCL, and its application in the synthesis of diacylglycerol by esterification of α‐linolenic acid with glycerol. The resin ECR8806 was selected as an effective support for the...
journal article 2018
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Šavija, B. (author), Smith, G.E. (author), Liu, D (author), Schlangen, E. (author), Flewitt, P.E.J. (author)
Deformation and fracture of materials are usually considered in terms of brittle and ductile modes. However, there is an intermediate class between these limits that is termed quasi-brittle where there is measurable inelastic deformation prior to final graceful ‘brittle’ failure. In previous work, we presented deformation and fracture data...
journal article 2018
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Abrahamsen, Asger Bech (author), Liu, D. (author), Magnusson, Niklas (author), Thomas, Arwyn (author), Azar, Ziad (author), Stehouwer, Ewoud (author), Hendriks, Ben (author), Van Zinderen, Gerrit-Jan (author), Deng, Fujin (author), Chen, Zhe (author), Karwatzki, Dennis (author), Mertens, Axel (author), Parker, Max (author), Finney, Stephen (author), Polinder, H. (author)
A method for comparing the levelized cost of energy (LCoE) of different superconducting drive trains is introduced. The properties of a 10-MW MgB<sub>2</sub> superconducting direct-drive generator and the cost break down of the nacelle components are presented and scaled up to a turbine with a rotor diameter of up to 280 m. The partial load...
journal article 2018
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Liu, D. (author), Tito, Nicholas B. (author), Broer, Dirk J. (author)
Coatings with a dynamic surface topography are of interest for applications in haptics, soft robotics, cell growth in biology, hydro- and air dynamics and tribology. Here we propose a design for creating oscillating surface topographies in thin liquid crystal polymer network coatings under an electric field. By applying an alternating...
journal article 2017
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Liu, D. (author)
In recent years, superconducting synchronous generators (SCSGs) have been proposed as an alternative to permanent magnet synchronous generators (PMSGs). They are expected to reduce the top head mass and the nacelle size for such large wind turbines. In 2012, the INNWIND.EU project initiated this research to investigate SCSGs for 10-20MWdirect...
doctoral thesis 2017
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Liu, D. (author), Polinder, H. (author), Abrahamsen, Asger B. (author), Ferreira, Jan Abraham (author)
This paper aims at assessing the potential of partially superconducting generators for 10 MW direct-drive wind turbines by investigating their performance for a very wide range of excitation currents. Performance indicators such as shear stress and efficiency and other generator characteristics are compared for 12 different generator topologies....
journal article 2017
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Abrahamsen, Asger Bech (author), Liu, D. (author), Magnusson, Niklas (author), Thomas, A (author), Z., Azar (author), Stehouwer, Ewoud (author), Hendriks, E (author), Penzkofer, A. (author), Atallah, K (author), Dragan, R.R. (author), .Clark, R.E. (author), Deng, F. (author), Chen, Z (author), Karwatzki, D. (author), Mertens, A. (author), Parker, M. (author), Finney, SJ (author), Polinder, H. (author)
Innovative drive trains targeted at 10-20 MW offshore turbines are investigated in the INNWIND.EU project in order to determine the impact on the Levelized Cost of Energy (LCoE) resulting when installed in the ,North sea at 50 m of water [1]. The two main technologies studied are superconducting direct drive (SCDD)[2] and the magnetic pseudo...
abstract 2017
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Song, X. (author), Liu, D. (author), Polinder, H. (author), Mijatovic, Nenad (author), Holbøll, Joachim (author), Jensen, Bogi Bech (author)
Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen at generator terminals. In this paper, a finite...
journal article 2017
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Wang, X. (author), Liu, D. (author), Lahaye, D.J.P. (author), Polinder, H. (author), Ferreira, Jan Abraham (author)
The brushless doubly-fed induction machine (DFIM) has great potential as a variable-speed generator for wind turbine applications. This special machine has a richer space-harmonic spectrum due to its special nested-loop rotor construction compared with conventional induction machines. It may result in higher iron losses, higher torque ripple and...
conference paper 2017
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Liu, D (author), Šavija, B. (author), Smith, G.E. (author), Flewitt, P.E.J. (author), Lowe, T. (author), Schlangen, E. (author)
In this work, porosity-property relationships of quasi-brittle materials are explored through a combined experimental and numerical approach. In the experimental part, hemihyrate gypsum plaster powder (CaSO 4 ⋅1/2H 2 O CaSO4⋅1/2H2O) and expanded spherical polystyrene beads (1.5–2.0 mm dia.) have been mixed to form a model material with...
journal article 2017
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Liu, D. (author), Kenjeres, S. (author)
In the present study, we address the development and application of an efficient tool for conversion of results obtained by an integrated computational fluid dynamics (CFD) and computational reaction dynamics (CRD) approach and their visualization in the Google Earth. We focus on results typical for environmental fluid mechanics studies at a...
journal article 2017
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Wang, X. (author), Liu, D. (author), Lahaye, D.J.P. (author), Polinder, H. (author), Ferreira, Jan Abraham (author)
Permanent-magnet machines with fractional slot concentrated windings are easy to manufacture. Their popularity therefore is steadily increasing. Without a proper design, however, the induced eddy-current losses in the solid rotor get rather high. The modeling and the prediction of eddy-current losses for these machines are thus very important...
conference paper 2016
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Liu, D. (author), Polinder, H. (author), Abrahamsen, Asger Bech (author), Ferreira, Jan Abraham (author)
Superconducting synchronous generators (SCSGs) are being proposed for 10-MW direct-drive wind turbines, because of their advantages of low weight and compactness. So far, however, there has not been a commonly accepted design philosophy of SCSGs and various possibilities with many tradeoffs remain for study. Partially SCSGs are considered a...
conference paper 2016
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Song, X. (author), Polinder, H. (author), Liu, D. (author), Mijatovic, Nenad (author), Holbøll, Joachim (author), Jensen, Bogi Bech (author)
Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen at generator terminals. In this paper, a finite...
conference paper 2016
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