It is a common phenomenon that the cracks originating from a hole can cause structural damage in ***,the fracture mechanics studies of hole edge crack problems are not *** problem of an elliptical hole with two collin...
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It is a common phenomenon that the cracks originating from a hole can cause structural damage in ***,the fracture mechanics studies of hole edge crack problems are not *** problem of an elliptical hole with two collinear edge cracks of unequal length in an infinite plate under uniform tension at infinity is *** on the complex variable method,the analytical solutions of stress functions and stress intensity factors are *** stress distribution along the axes and the edge of the elliptical hole is given *** numerical results show that there is obvious stress concentration near the hole and cracks,and the stresses tend to applied loads at distances far from the defect,which conform to Saint-Venant’s ***,the stress functions are proved to be *** special conditions,the present configuration becomes the Griffith crack,two symmetrical cracks emanating from an elliptical hole,two cracks of unequal length emanating from a circular hole,a crack at the edge of a circular hole,or a crack emanating from an elliptical *** with available results,stress intensity factors for these special shapes of ellipses and cracks show good *** stress intensity factor for two cracks of unequal length at the edge of an elliptical hole increases with the crack length and the major-to-minor axis ratio of the elliptical *** stress distribution in an infinite plate containing an elliptic hole with unsymmetrical cracks is given for the first time.
Crack detection is very important for long-term large-scale structural healthmonitoring (SHM). Fiber optic sensor has been approved to have good performance in application in SHM. In this paper, we present a novel me...
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Very recently,organic–inorganic lead halide based perovskites (CH3NH3PbX3(X:Cl,Br,or I)) have emerged as a new class of light absorbers for thin film solar cells.[1] A PCE exceeding 15% was realized recently with two...
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Very recently,organic–inorganic lead halide based perovskites (CH3NH3PbX3(X:Cl,Br,or I)) have emerged as a new class of light absorbers for thin film solar cells.[1] A PCE exceeding 15% was realized recently with two-step solution Deposition on the mesoporous TiO2 film[2],and this method has attracted great attentions.
Crack detection is very important for long-term large-scale structural healthmonitoring(SHM).Fiber optic sensor has been approved to have good performance in application in *** this paper,we present a novel method to...
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Crack detection is very important for long-term large-scale structural healthmonitoring(SHM).Fiber optic sensor has been approved to have good performance in application in *** this paper,we present a novel method to monitoring the crack by using long-gauge FBG sensor.A FBG with a gauge length of 50 mm is *** the crack pass through the FBG,the reflect spectrum of FBG will be expanded or *** position of the crack will result in different Shape of the *** analyzing the characteristics of the spectrum,the position of the crack can be detected and the opening width of the crack can be estimated.
This study aims at providing a practical method in large structure healthmonitoring. A novel fiber optic rosette based on distributed feedback (DFB) fiber laser for acoustic emission (AE) detection and location is pr...
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In this paper, a novel fiber optic concrete sensor based on extrinsic fiber Fabry-Perot interferometer (EFPI) is designed and analyzed. Two fiber ends are inserted into a glass capillary and encapsulated into a cement...
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ISBN:
(纸本)9780819465368
In this paper, a novel fiber optic concrete sensor based on extrinsic fiber Fabry-Perot interferometer (EFPI) is designed and analyzed. Two fiber ends are inserted into a glass capillary and encapsulated into a cement cylinder to act as the sensor head. In this way, the cement cylinder itself is the sensor head instead of the traditional steel tube, which makes it very convenient to embed the sensor head into the concrete, because the cement consists with the concrete well. Based on the theory of white light interferometry and the theory of elasticity, the wavelength modulation method and the strain transfer are analyzed theoretically. The demodulation system is also introduced in this paper. The experiment being made by our research group is aimed at testing the consistency, stability, reliability and the sensitivity of the fiber optic sensor. The sensor head of the cement cylinder is embedded into a model ferroconcrete beam together with traditional strain gauges. The experiment is carried out using the PEM-500A hydraulic pulsation fatigue test machine after 2 million stress circles. The readout of the fibre optic sensor and the strain gauges is recorded and made a contrast. It can be found from the result that the fibre optic sensors have good stability and reliability, the accuracy for the fibre optic sensor is better than 0.5 micro-strain, which shows that the sensor can meet the demand of the long-term monitoring of large-size concrete structure.
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