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Xie, J. (author), Xu, Y. (author), Meng, Z. (author), Liang, M. (author), Wan, Z. (author), Šavija, B. (author)Auxetic cementitious cellular composites (ACCCs) exhibit desirable mechanical properties (e.g., high fracture resistance and energy dissipation), due to their unique deformation characteristics. In this study, a new type of cementitious auxetic material, referred to as peanut shaped ACCC, has been designed and subsequently architected using...journal article 2024
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Wan, Z. (author), Xu, Y. (author), Chang, Z. (author), Liang, M. (author), Šavija, B. (author)Vascular self-healing concrete (SHC) has great potential to mitigate the environmental impact of the construction industry by increasing the durability of structures. Designing concrete with high initial mechanical properties by searching a specific arrangement of vascular structure is of great importance. Herein, an automatic optimization...journal article 2024
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Wan, Z. (author), Xu, Y. (author), He, S. (author), Schlangen, E. (author), Šavija, B. (author)This paper presents a state-of-the-art review on the application of additive manufacturing (AM) in self-healing cementitious materials. AM has been utilized in self-healing cementitious materials in three ways: (1) concrete with 3D-printed capsules/vasculatures; (2) 3D concrete printing (3DCP) with fibers or supplementary cementitious...journal article 2024
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Xu, Y. (author)Micro air vehicles (MAVs) have shown significant potential in modern society. The development in robotics and automation is changing the roles of MAVs from remotely controlled machines requiring human pilots to autonomous and intelligent robots. There is an increasing number of autonomous MAVs involved in outdoor operations. In contrast, the...doctoral thesis 2023
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Wan, Z. (author), Xu, Y. (author), Šavija, B. (author)Compared with other self-healing mechanisms, embedding vascular networks in cementitious matrix enables repairing wider cracks and performing multiple healing cycles. For vascular-based self-healing cementitious composites, additive manufacturing (AM) allows fabricating vascular structures with complex geometry. For Fused Filament Fabrication ...book chapter 2023
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Xu, Y. (author), de Croon, G.C.H.E. (author)In this paper, we propose a learning-based lightweight visual-inertial odometry (VIO) based on an uncertainty-aware pose network and an extended Kalman filter (EKF). The pose network serving as the VIO vision front-end predicts the relative motion of the camera between consecutive image frames and estimates the prediction uncertainty. The...conference paper 2023
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Xu, Y. (author), de Croon, G.C.H.E. (author)When deployed onboard micro air vehicles (MAVs) with limited processing power, visual ego-motion estimation solutions face an efficiency-accuracy trade-off. This paper proposes an aerodynamic-model-aided approach that emphasizes time efficiency over estimation accuracy. A linear drag force model of propellers guarantees bounded estimation errors...conference paper 2023
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Wan, Z. (author), Chang, Z. (author), Xu, Y. (author), Šavija, B. (author)In this paper, optimization of vascular structure of self-healing concrete is performed with deep neural network (DNN). An input representation method is proposed to effectively represent the concrete beams with 6 round pores in the middle span as well as benefit the optimization process. To investigate the feasibility of using DNN for...journal article 2023
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Xu, Y. (author), Reniers, G.L.L.M.E. (author), Yang, M. (author), Yuan, S. (author), Chen, Chao (author)Domino accidents are typical low-frequency and high-consequence events in chemical process industries. Applying quantitative risk assessment (QRA) in domino accident assessment is challenging due to the uncertainties in the escalation process. Meanwhile, the outcomes of QRA are subject to a certain degree of unreliability due to the...journal article 2023
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Xu, Y. (author), Krishnakumari, P.K. (author), Yorke-Smith, N. (author), Hoogendoorn, S.P. (author)COVID-19 significantly influenced travel behaviours and public attitudes towards public transport. Various studies have illustrated complicated factors related to long-term travel behaviour, indicating difficulty in understanding and predicting post-pandemic long-term travel behaviour via traditional methods. In these complex circumstances,...conference paper 2023
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Xu, Y. (author), Šavija, B. (author)Auxetic cementitious composites (ACCs) with improved mechanical properties are created, by casting 3D printed polymeric auxetic reinforcement structures inside cementitious mortar. Four types of ACCs incorporating reinforcement with different auxetic mechanisms were prepared: “re-entrant” (RE), “rotating-square” (RS), “chiral” (CR) and ...journal article 2023
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Xu, Y. (author), Zhang, Xiao Zheng (author), Casalino, D. (author), Bi, Chuan Xing (author)An inverse acoustic method is presented in this work, which allows to determine the spatial and temporal distribution of unsteady rotating forces from microphone array measurements. The method is based on the usage of a space–time regularization with a mixed norm. The proposed method can take advantage of a prior knowledge of the space–time...journal article 2023
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Xu, Y. (author), Šavija, B. (author)A composite can have properties much better than the components it is made of. This work proposes a three-dimensional auxetic cementitious-polymeric composite structure (3D-ACPC) which incorporates 3D printed polymeric shell with cementitious mortar. Uniaxial compression experiments are performed on the 3D-ACPC to study their quasi-static...journal article 2023
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Wan, Z. (author), Xu, Y. (author), He, S. (author), Chen, Y. (author), Xie, J. (author), Šavija, B. (author)Direct ink writing of cementitious materials can be an alternative way for creating vascular self-healing concrete by intentionally incorporating hollow channels in the cementitious matrix. In this study, a 3D-printable fibre reinforced mortar was first developed. Three groups of specimens were fabricated using direct ink writing, where the...journal article 2023
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Xie, J. (author), Xu, Y. (author), Wan, Z. (author), Ghaderiaram, A. (author), Schlangen, E. (author), Šavija, B. (author)The high deformation capacity of auxetic cementitious cellular composites (ACCCs) makes them promising for strain-based energy harvesting applications in infrastructure. In this study, a novel piezoelectric energy harvester (PEH) with ACCCs and surface-mounted PVDF film based on strain-induced piezoelectric mechanisms has been designed,...journal article 2023
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Wan, Z. (author), Zhang, Y. (author), Xu, Y. (author), Šavija, B. (author)Additively manufactured vascular networks have great potential for use in autonomous self-healing of cementitious composites as they potentially allow multiple healing events to take place. However, the existence of a vascular tube wall may impede with the healing efficiency if it does not rupture timely to release the healing agent. The...journal article 2023
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Chang, Z. (author), Liang, M. (author), Xu, Y. (author), Wan, Z. (author), Schlangen, E. (author), Šavija, B. (author)In this study, an experimental setup to characterize the early-age creep of 3D printable mortar was proposed. The testing protocol comprises quasi-static compressive loading-unloading cycles, with 180-s holding periods in between. An analytical model based on a double power law was used to predict creep compliance with hardening time and...journal article 2023
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Xu, Y. (author), Luo, D. (author), Qian, QK (author), Chan, Edwin H.W. (author)In the original publication of the article, the first affiliation “School of Public Administration, Hunan University, Changsha, China” was incorrectly repeated as fourth affiliation. The fourth affiliation should be “Building and Real Estate Dept. Hong Kong Polytechnic University, Hong Kong SAR”. The original article has been corrected.journal article 2023
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Chang, Z. (author), Wan, Z. (author), Xu, Y. (author), Schlangen, E. (author), Šavija, B. (author)Extrusion-based 3D concrete printing (3DCP) results in deposited materials with complex microstructures that have high porosity and distinct anisotropy. Due to the material heterogeneity and rapid growth of cracks, fracture analysis in these air-void structures is often complex, resulting in a high computational cost. This study proposes a...journal article 2022
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Xu, Y. (author), Reniers, G.L.L.M.E. (author), Yang, M. (author), Yuan, S. (author), Chen, C. (author)Data uncertainties caused by the lack of knowledge and nature variation or randomness present vital challenges to domino effects modelling. To improve the assessment of the propagation probabilities and consequences of the domino-effect accidents, the influence of various types of uncertainties on risk assessment results needs to be investigated...journal article 2022