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In this paper, static performances of a new precast concrete arch system with carbon fiber reinforced polymer (CFRP) reinforcement were investigated. Varied concrete strengths and segment types of precast concrete arches were tested. The results show that the increase of concrete strength can improve the bearing capacity of the precast arches with CFRP reinforcement. The ultimate bearing capacity of the precast arches segmented at the arch vault with CFRP reinforcement can reach or even exceed that of complete arches, while the precast arch segmented at the shoulder had lower ultimate load. A theoretical analysis method was proposed to predict the failure and bearing capacity of the precast concrete arches with CFRP reinforcement, which were found to be in close agreement with the experimental result. [ABSTRACT FROM AUTHOR]

With the increasing number of violent terrorist attacks around the world, it is quite a common to improve the anti-blast performance of structures by reinforcing the exterior of the structure. In order to explore the dynamic performance of polyurea reinforced concrete arch structures, a three-dimensional finite element model was established by LS-DYNA software in this paper. Under the condition of ensuring the validity of the simulation model, the dynamic response of the arch structure under the blast load is investigated. Deflection and vibration of the structure under different reinforcement models are discussed. The optimum thickness of reinforcement (approximately 5 mm) and the strengthening method for the model were found by deformation analysis. The vibration analysis shows that the vibration damping effect of the sandwich arch structure is relatively excellent, but increasing the thickness and number of layers of the polyurea does not necessarily achieve a better vibration damping function for the structure. By reasonable design of the polyurea reinforcement layer and concrete arch structure, a protective structure with excellent performance of anti-blast and vibration damping can be created. Polyurea can be used as a new form of reinforcement in practical applications. [ABSTRACT FROM AUTHOR]

In this study, based on the free-rolling mechanism of the auxetic honeycomb, a honeycomb cylindrical shell was successfully prepared to overcome the fracture problem of the hexagonal honeycomb during rolling. Auxetic honeycomb sandwich tubes (AHSTs) with a variable Poisson's ratio were fabricated by molding and bonding. A Poisson's ratio model of the auxetic honeycomb core was developed based on the strain increment ratio of the deformed honeycomb and validated using computed tomography (CT). Four failure modes (progressive stable fold mode I, unstable local buckling mode II, transverse shearing mode III, and mid-length collapse mode IV) of the AHST were summarized by comparing the deformation behavior and force–displacement curves with different geometric parameters. When the aspect ratio R is greater than 3, the AHST will be more easily damaged in instability (Mode IV). Static compression tests showed that the peak force (PF) and crushing force efficiency (CFE) of the AHST were higher than those of the CFRP thin-walled tube of the same diameter by 78% and 115%, respectively. Therefore, the AHST has excellent mechanical properties and it is feasible to use the auxetic honeycomb as a core for sandwich structures. [ABSTRACT FROM AUTHOR]

This paper studies the effectiveness of bonding carbon fiber reinforced polymer (CFRP) with additional wraps or anchors to strengthen reinforced concrete (RC) arches resisting blast loads, which is of great significance to optimize the CFRP strengthening methods. To improve the anti‐explosion behavior, RC arches are bonded with CFRP sheets in longitudinal and transverse directions, and anti‐explosion behaviors were investigated through experiments. The performance of strengthened arches is discussed in terms of damage degrees in contrast to the un‐strengthened arch. Under explosive loading, the resistance of composite arches to spalling, shearing, and bending is much better than that of control arch. The results show that the anti‐explosion effect of wrapping or anchoring, which can prevent CFRP debonding or peeling‐off, is much better than only bonding CFRP in the longitudinal direction. Besides, simplified analysis models are proposed to assess the blast‐resistant capacity of CFRP strengthened RC arches, which show good agreement with the experiment. [ABSTRACT FROM AUTHOR]

We propose a dust removal technology in which a two-stage moving granular bed filter was employed using coarse and fine filtering granules. The pressure drop, collection efficiency, and dust particulate size distributions were investigated using various mass flow rates for coarse and fine granules at room temperature. In addition, the ratio of mass consumption was used to reveal the actual mass flow. The ratio of mass consumption influenced the pressure drop, collection efficiency, and dust particulate size distributions. Particulates larger than 1.775 μm were removed by the filter. Our results showed that a mass flow of 330 g/min for coarse granules and a mass flow of 1100 g/min for fine granules provided optimal collection efficiency and particulate size distribution. The proposed design can aid the development of high-temperature systems in power plants. [ABSTRACT FROM AUTHOR]

Dynamic network is an abstraction of networks with frequent topology changes arising from node mobility or other reasons. In this article, we first propose a dynamic network model, named (T, L)-HiNet, to extend existing dynamic network models with clusters. (T, L)-HiNet includes several properties defining the stability of cluster hierarchy in a dynamic network, including cluster head set, cluster member set and the connections among them. Based on (T, L)-HiNet, we design several hierarchical information dissemination algorithms for different scenarios of dynamics. Furthermore, we extend the (T, L)-HiNet model and corresponding algorithms in two directions, that is, stability of cluster head set and cluster size. The correctness of our algorithms is proved rigorously, and their performance is evaluated via both numerical analysis and simulations. The results show that compared with the algorithm recently proposed by Kuhn et al., our design can significantly reduce communication cost and also time cost. [ABSTRACT FROM AUTHOR]

• Explosion attenuation composite sandwich meta-panels were designed, made and tested. • The bandgap width of the meta-panel can reach 300 Hz for flexural waves. • The peak displacement under blast load can be reduced to 70% of that of ordinary sandwich panel. In this research, composite sandwich meta-panels were designed, made and tested. The vibration and explosion attenuation effects of the meta-panel were revealed by frequency sweep tests, in-field explosion experiments, and finite element modeling (FEM). Meta-panel theory was also applied to predict the dynamic behavior. The local resonance metamaterial panel shows extraordinary vibration attenuation and explosion mitigation effects. The bandwidth of the meta-panel can reach 300 Hz, and the peak displacement can be reduced to 70% or less of that of the ordinary sandwich panel. The peak strain of the facesheet is reduced as well. The research provides an experimental basis for the application of metamaterials in protective buildings. [ABSTRACT FROM AUTHOR]