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Quality assessment and damage detection in nanomodified adhesively-bonded composite joints using inkjet-printed interdigital sensors
摘要： In this work, the development of a planar interdigital capacitive sensor, directly onto the surface of a composite, for determining the initial quality of curing of bonded composite joints and assessing their long-term durability is presented. The sensor consisted of an interlocking comb-shaped array of silver electrodes and used to monitor the progress of cure of an adhesive resin and the subsequent damage state of the bond line in adhesively-bonded composite joints using impedance spectroscopy. The obtained results from the mechanical characterization indicated that the developed sensor did not affect the quality of the bondline while the added weight of the sensor is negligible. The curing process of the adhesive epoxy was successfully monitored while the ability of the sensor to assess the developed damage created by the mechanical loading was confirmed using transient infrared thermography.
关键词： quality assessment,inkjet printing,Bonded composite structures,damage detection,interdigital sensors
更新于2025-09-23 15:23:52
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In-situ synthesis of mullite-SiCw composite ceramics in Li2O-Al2O3-SiO2 ternary system for solar heat transmission pipeline
摘要： Nano-SiC whiskers (nano-SiCw) were in-situ synthesized in Li2O-Al2O3-SiO2 ternary system for preparing highly densified mullite-SiCw composite ceramics used for solar heat transmission pipeline. Mechanisms on the in-situ synthesis of nano-SiCw in the ternary system were investigated and the impact of nano-SiCw on the performances of the composites had been studied. Results showed that the growth processes of nano-SiC whiskers in Li2O-Al2O3-SiO2 ternary system were dominated by liquid-solid (LS) mechanism and the Li2CO3 additive could improve the SiCw yield through increasing the content of liquid phase and lowering the liquid viscosity. Sample BS3 (with 2.22 wt% Li2CO3 additive) sintered at 1440 °C obtained the highest SiC content of 47.9%. Nano-SiC whiskers with a diameter of 20e30 nm were interlocking with rod-like mullite crystals to improve the mechanical properties of the composites, and sample BS1 sintered at 1420 °C showed the highest bending strength of 115.4 MPa. The in-situ synthesized SiCw also shew significant effects on improving the thermophysical properties of the composites and sample BS1 exhibited a 3.6 times higher thermal conductivity than that of blank sample B1 without the introduction of nano-SiCw.
关键词： Li2O-Al2O3-SiO2 ternary system,Thermal conductivity,Mullite-SiCw composite ceramics,Solar heat transmission pipeline,SiC whiskers
更新于2025-09-23 15:23:52
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Experimental Study of the Stress-Strain State Features of Outlet Guide Vane Made From Polymer Composite Material Using Fiber Optic Sensors
摘要： An estimation technique for the stress-strain state of the outlet guide vane design of an aircraft propulsion system made of polymer composite materials (PCM) using fiber-optic sensors is proposed. Fiber-optic sensors allow creating details with the possibility of self-diagnosis and forecasting the resource of work. This issue is particularly relevant when using PCM in highly loaded aircraft engine elements. The object of the study is the outlet guide vane (OGV) made of an equally strong carbon cloth on an epoxy binder. The tests were carried out on a universal servo-hydraulic machine. The data from fiber-optic sensors was carried out using an interrogator ASTRO X327. The comparison of the experiment and the numerical calculation were performed using the software package ANSYS.
关键词： polymer composite material,fiber optic sensors,numerical calculations,stress-strain state
更新于2025-09-23 15:23:52
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Preparation of MoS <sub/>2</sub> @ZnO heterostructure with enhanced photocatalytic activity
摘要： In order to effectively solve environmental problems induced by organic pollutants, the MoS2@ZnO heterostructure is successfully fabricated via a two-step hydrothermal method, in which the MoS2 nanosheets grew on the surface of ZnO nanorods. The synthetic heterostructure is demonstrated to possess excellent photocatalytic activity in the degradation of methylene blue (MB) under ultraviolet (UV) and visible light irradiation. The corresponding photodegradation rate constant of MoS2@ZnO heterostructure reaches up to 0.02075 min-1 and 0.00916 min-1, which are higher than that of pure ZnO (0.00514 min-1 and 0.00048 min-1) under the same reaction conditions. Obviously, compared with pure ZnO, the photocatalytic activity of the MoS2@ZnO heterostructure has been significantly improved. This could be attributed to the increased specific surface area of photocatalyst and the formation of heterostructure between ZnO and MoS2 after loading the MoS2 on the surface of ZnO nanorods. Which help to provide more reaction sites for the adsorption of pollutant and improve the separation efficiency of photogenerated electron-hole pairs.
关键词： MoS2,composite materials,ZnO,photocatalytic activity,heterostructure
更新于2025-09-23 15:22:29
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Fibre Bragg grating sensor applications for structural health monitoring
摘要： Purpose – Structural health monitoring (SHM) has become an attractive subject in aerospace engineering ?eld considering the opportunity to avoid catastrophic failures by detecting damage in advance and to reduce maintenance costs. Fibre Bragg Grating (FBG) sensors are denoted as one of the most promising sensors for SHM applications as they are lightweight, immune to electromagnetic effects and able to be embedded between the layers of composite structures. The purpose of this paper is to research on and demonstrate the feasibility of FBG sensors for SHM of composite structures. Design/methodology/approach – Applications on thin composite beams intended for SHM studies are presented. The sensor system, which includes FBG sensors and related interrogator system, and manufacturing of the beams with embedded sensors, are detailed. Static tension and torsion tests are conducted to verify the effectiveness of the system. Strain analysis results obtained from the tests are compared with the ones obtained from the ?nite element analyses conducted using ABAQUS? software. In addition, the comparison between the data obtained from the FBG sensors and from the strain gauges is made by also considering the noise content. Finally, fatigue test under torsion load is conducted to observe the durability of FBG sensors. Findings – The results demonstrated that FBG sensors are feasible for SHM of composite structures as the strain data are accurate and less noisy compared to that obtained from the strain gauges. Furthermore, the convenience of obtaining reliable data between the layers of a composite structure using embedded FBG sensors is observed. Practical implications – Observing the advantages of the FBG sensors for strain measurement will promote using FBG sensors for damage detection related to the SHM applications. Originality/value – This paper presents applications of FBG sensors on thin composite beams, which reveal the suitability of FBG sensors for SHM of lightweight composite structures.
关键词： Torsion test,Tension test,Structural health monitoring,Composite beams,Fibre Bragg grating sensors
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Wide-Angle Frequent Scanning Metamaterial Leaky Wave Antenna Array for Automotive Radars
摘要： This paper designs a wide-angle frequency scanning metamaterial (MTM) leaky wave antenna (LWA) array for automotive radars. The gap capacitors and the vialess open stub-loaded resonators are used to construct the frequency scanning MTM LWA array. The propagation constant of the MTM LWA array is able to change from negative to positive values as the frequency is increased, resulting in backward to forward beam scanning. Compared to mechanical beam scanning arrays and phased arrays, the frequency scanning MTM LWA arrays have advantages of reducing the system complexity, light weight and low cost. The presented MTM LWA array has a maximum gain of 13 dB and wide scanning angle from -60° to +80° as the frequency varies from 23.5 to 25.6 GHz which is well suited for automotive radar applications.
关键词： frequency scanning antenna,composite right/left-handed transmission line,Antenna array,metamaterial,leaky wave antenna
更新于2025-09-23 15:22:29
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The Comparison of the Photocatalytic Performance Shown by TiO <sub/>2</sub> and TiO <sub/>2</sub> /WO <sub/>3</sub> Composites— A Parametric and Kinetic Study
摘要： Kinetic and mechanistic related approaches for mostly titania were intensively studied in the literature. However, combined modelling and kinetic studies are few. Therefore, the present work focuses on modelling the dependence of the degradation kinetics of two model compounds (salicylic acid—SA and methyl orange—MO) on Evonik Aeroxide P25, hydrothermally prepared hierarchical TiO2 and P25/WO3 nanostars, obtained also by hydrothermal crystallization. The obtained individual semiconductors and the composites were characterized using XRD, DRS, SEM, while the photocatalytic degradation of the model pollutants were carried out varying the catalyst load, the initial pollutant concentration and incident light intensity. It was found that the degradation kinetics were independent from the hierarchical nature of the material, while significant dependencies of the degradation efficiency was found from the previously mentioned investigation parameters. All these parametric interdependences were successfully studied and a kinetic model was proposed for both bare TiO2 and TiO2/WO3 composite systems.
关键词： Degradation,Salicylic Acid,Methyl Orange,Kinetic Modelling,Composite Materials
更新于2025-09-23 15:22:29
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Novel polyelectrolyte–Al2O3/SiO2 composite nanoabrasives for improved chemical mechanical polishing (CMP) of sapphire
摘要： A new type of polyelectrolyte–Al2O3/SiO2 composite nanoparticle with excellent dispersibility and superior polishing performance was successfully fabricated using a facile method. Silica acted as a bifunctional molecule by attaching to alumina via covalent bond and adsorbing polyelectrolytes by electrostatic interaction. The material removal rate of the polyelectrolyte–Al2O3/SiO2 abrasive was 30% higher than that of the pure Al2O3 abrasive. In addition, the sapphire surface was much smoother. The material removal mechanism was investigated during CMP using the microcontact and wear model. The enhanced removal rate was mainly attributed to the well-dispersed particles, which can accelerate mechanical removal process. The remarkably smooth surface was due to the decrease in penetration depth of the abrasive into the wafer. The results of this study provided a feasible strategy to satisfy the high efficiency and damage-free polishing requirements for sapphire planarization.
关键词： chemical mechanical polishing,composite abrasives,polyelectrolyte,surface roughness,sapphire,material removal rate
更新于2025-09-23 15:22:29
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High-Temperature Filter Based on Silicon Carbide for Aggressive Fluids and Gases
摘要： In this paper, we developed a production method for items based on mesh silicon carbide that are suitable for cleaning aggressive fluids, melts, and gases from foreign inclusions at high operating temperatures. The resulting products can also be used for filtering fuel mixtures.
关键词： carbon fibers,silicization,silicon carbide,microstructure,composite filter
更新于2025-09-23 15:22:29
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Opto-electronic platform tracking control of multi-rotor unmanned aerial vehicles based on composite disturbance compensation
摘要： Airborne opto-electronic platforms are very important in unmanned aerial vehicle systems. The stability and tracking performance of airborne opto-electronic platforms are easily affected by disturbance factors, making compensating for those disturbances a very prominent issue. In this paper, compared to the traditional disturbance observer, an improved velocity signal based disturbance observer (IVDOB) is particularly designed to compensate for the disturbance. Then its capability, robustness, and stability are discussed. For improving the stabilization accuracy and tracking performance of airborne opto-electronic platforms, the universal approximation property of fuzzy systems is used to compensate the disturbance further and an adaptive fuzzy control system based on IVDOBs is proposed. To validate the scheme, a series of experiments were carried out. The results show that the proposed control scheme can achieve reliable control precision and satisfy the requirements of airborne opto-electronic platform tasks.
关键词： Multi-rotor unmanned aerial vehicle,airborne opto-electronic platform,composite disturbance compensation,disturbance observer,approximation property
更新于2025-09-23 15:22:29