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- 摘要
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[Sustainable Civil Infrastructures] Advances and Challenges in Structural Engineering (Proceedings of the 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The Official International Congress of the Soil-Structure Interaction Group in Egypt (SSIGE)) || Utilization of Ground Penetrating Radar (GPR) in the Non-destructive Assessment of FRP Laminate-Concrete Bond Strength
摘要： Repair and rehabilitation methods for civil infrastructure have become a topic of great interest to engineers, and fiber reinforced polymer (FRP) laminate is one of the most popular and practical solutions for strengthening and retrofitting of concrete structures. Several past studies indicated that significant increase in strength and stiffness can be achieved by using this technology. The quality of the FRP-concrete bond is critical in transferring stresses through the interface, and the in-situ evaluation of the bond strength is still a challenging issue. To quantitatively evaluate the bond strength, non-destructive technique (NDT) using ground penetrating radar (GPR) was utilized on 32 laboratory concrete beams strengthened with carbon FRP (CFRP) laminates. Various parameters that may affect the bond strength, such as surface roughness, voids, epoxy type and thickness, and FRP type, were considered. The experiment was conducted with the objective of non-destructively detecting the parameters. The associated bond capacity of each sample was then found through a three-point bending test and also correlated through finite element modeling. Quantitative relationships between each of the parameters in the study and the associated bond strengths were then developed. The results of this study will be very useful in estimating the in-service bond conditions of applied FRP laminate, thereby estimating the expected strength contribution of the laminate in the overall flexural strength of structural members.
关键词： Ground Penetrating Radar,Non-destructive Testing,FRP,Concrete Structures,Bond Strength
更新于2025-09-10 09:29:36
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Optical vortex phase determination for nanoscale imaging
摘要： In this research we develop a principle of optical vortex phase analysis and its application to surface imaging with high accuracy measurements in nanoscale range. Two-coordinate scanning of the sample allow to retrieve an information about shape and roughness for optically transparent and reflecting surfaces exceeding optical diffraction limit. The interference between singular beam and reference wave, in general, carrying optical vortex with single or doubled topological charge allow to extract the data about phase delay caused by surface features or refraction. This method is also applicable for non-destructive testing of biological structures and live cells in real-time regime. Automatic processing of vortex interferograms allow to achieve a vertical and longitudinal resolution down to 1,75 nm and 7 nm respectively for visible light sources.
关键词： biological structures,nanoscale imaging,surface roughness,non-destructive testing,optical vortex phase analysis
更新于2025-09-09 09:28:46
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Electromagnetic Acoustic Transducers Applied to High Temperature Plates for Potential Use in the Solar Thermal Industry
摘要： Concentrated Solar Plants (CSPs) are used in solar thermal industry for collecting and converting sunlight into electricity. Parabolic trough CSPs are the most widely used type of CSP and an absorber tube is an essential part of them. The hostile operating environment of the absorber tubes, such as high temperatures (400–550 °C), from creep, contraction/expansion, and vibrations, may lead them to suffer thermo-mechanical fatigue, and hot corrosion. Hence, their condition monitoring is of crucial importance and a very challenging task as well. Electromagnetic Acoustic Transducers (EMATs) are a promising, non-contact technology of transducers that has the potential to be used for the inspection of large structures at high temperatures by exciting Guided Waves. In this paper, a study regarding the potential use of EMATs in this application and their performance at high temperature is presented. A Periodic Permanent Magnet (PPM) EMAT with a racetrack coil, designed to excite Shear Horizontal waves (SH0), has been theoretically and experimentally evaluated at both room and high temperatures.
关键词： non-destructive testing,high temperatures,Electromagnetic Acoustic Transducer (EMAT),solar thermal plants,guided waves
更新于2025-09-09 09:28:46
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Free-Space Materials Characterization by Reflection and Transmission Measurements using Frequency-by-Frequency and Multi-Frequency Algorithms
摘要： The knowledge of the electromagnetic constitutive properties of materials is crucial in many applications. Free-space methods are widely used for this purpose, despite their inherent practical difficulties. This paper describes an affordable free-space experimental setup for the characterization of flat samples in 1–6 GHz in a non-anechoic environment. The extracted properties are obtained from the calibrated Scattering Parameters, using a frequency-by-frequency solution or a multi-frequency reconstruction. For the first, we describe how the Time-Domain Gating can be implemented and used for filtering the signals. For the latter, a weighting factor is introduced to balance the reflection and transmission data, allowing one to have a more favorable configuration. The different role of transmission and reflection measurements on the achievable results is analyzed with regard to experimental uncertainties and different noise scenarios. Results from the two strategies are analyzed and compared. Good agreement between simulation, measurement and literature is obtained. According to the reported results for dielectric materials, there is no need of filtering the data by a Time-Domain Gating in case of the multi-frequency approach. Experimental results for Polymethylmethacrylate (PMMA) and Polytetrafluorethylene (PTFE) samples validate both the setup and the processing.
关键词： free-space method,permeability,conductivity,non-destructive testing,extraction algorithms,permittivity,time-domain gating,free-space calibration,scattering parameters,material characterization
更新于2025-09-09 09:28:46
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An overview of corrosion defect characterization using active infrared thermography
摘要： Corrosion is considered a destructive phenomenon that affects almost all metals. There is a variety of corrosion monitoring and measurement techniques being deployed across industries. However, very few techniques are ideally characterised with non-contact, non-intrusive, on-line and direct features for measuring the accurate corrosion rate or actual metal loss. Infrared Thermography (IRT) allows the recording of electromagnetic waves emitted from objects by using an infrared imaging system, such as an infrared camera. IRT is an online method of Non-Destructive Testing (NDT) meaning the delays in receiving results from a laboratory experienced in many NDT techniques can be eliminated. It is non-intrusive which means no process disruption and downtime will be imposed to the production line. It is also a non-contact method which mitigates the hazard occurrence and need for highly experienced personnel.
关键词： Infrared thermography,Non-destructive testing,Corrosion monitoring,Structural health monitoring,Image processing
更新于2025-09-04 15:30:14
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Error-Splitting Forward Model for Iterative Reconstruction in X-ray Computed Tomography and application with Gauss-Markov-Potts prior
摘要： In order to enhance image quality for controlling the interior of a volume in industry, model-based iterative reconstruction (MBIR) methods in 3D X-ray Computed Tomography (CT) have shown their efficiency compared to analytical reconstruction methods. MBIR methods enforce a prior model on the volume to reconstruct and make fusion of the information contained in the prior model and the projection data. The projections have many uncertainties which have very different origins in 3D CT. They are taken into account in MBIR methods but, despite of their different origins, they are in general gathered in only one term in the forward model. In this paper, we propose to derive a new forward model by adding a further error term in the Poisson statistics of photon-count, corresponding to the deviation of the monochromatic model with respect to the actual polychromacy of the rays. A Taylor expansion of the Poisson log-likelihood leads us to a new algebraic forward model accounting for two terms of uncertainties : we call it the error-splitting forward model. Different prior models are assigned to each of distinguished uncertainties : measurement uncertainties are modeled as Gaussian, while linear model uncertainties are modeled as heavy-tailed to bring robustness to the reconstruction process. We give strategies to fix the parameters of the error-splitting forward model. Next, we use it in a full MBIR method with Gauss-Markov-Potts prior model on the volume, in order to reconstruct piecewise-constant objects for non-destructive testing in industry. Compared to the conventional forward model, we show in our experiments that the use of the error-splitting forward model with Gauss-Markov-Potts prior combines better robustness and accuracy.
关键词： 3D Computed Tomography,iterative reconstruction,Gauss-Markov-Potts,error-splitting,forward model,Bayesian approach,non-destructive testing
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow, Poland (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Development of an iTomography infrastructure for non-destructive documentation of cultural heritage objects
摘要： In this paper, an new setup for the non-destructive scanning for cultural heritage applications is proposed. First, a multi-degree of freedom mechanical implementation is designed, for multiple angle and distance scanning of artworks via different modalities. Moreover, a specialized acquisition and control software is developed consequently created for the uni?ed platform. Additionally, various, onboard, post-processing image registration algorithms are realized for the combination of images originating on various sensors. The ?nal setup is tested on a mock-up icon, verifying the merits of the developed prototype for cultural heritage science work and research.
关键词： mapping tomography,ultrasound,spectroscopy,image processing,heritage science,non destructive testing
更新于2025-09-04 15:30:14