Underground Pipeline Identification into a Non-Destructive Case Study Based on Ground-Penetrating Radar Imaging

Ground-penetrating radar (GPR) has become one of the key technologies in subsurface sensing and, in general, in nondestructive testing (NDT), since it is able to detect both metallic and nonmetallic targets. GPR has proven its ability to work in electromagnetic frequency range for subsoil investigations, and it is a risk-reduction strategy for surveying underground various targets and their identification and detection. This paper presents the results of a case study which exceeds the laboratory level being realized in the field in a real case where the scanning conditions are much more difficult using GPR signals for detecting and assessing underground drainage metallic pipes which cross an area with large buildings parallel to the riverbed. The two urban drainage pipes are detected based on GPR imaging. This provides an approximation of their location and depth which are convenient to find from the reconstructed profiles of both simulated and practical GPR signals. The processing of data recorded with GPR tools requires appropriate software for this type of measurement to detect between different reflections at multiple interfaces located at different depths below the surface. In addition to the radargrams recorded and processed with the software corresponding to a GPR device, the paper contains significant results obtained using techniques and algorithms of the processing and post-processing of the signals (background removal and migration) that gave us the opportunity to estimate the location, depth, and profile of pipes, placed into a concrete duct bank, under a structure with different layers, including pavement, with good accuracy

Structural Testing by Torsion of Scalable Wind Turbine Blades

In life service, the wind turbine blades are subjected to compound loading: torsion, bending, and traction, all these resulting in the occurrence of normal and tangential stresses. At some points, the equivalent stresses, due to overlapping effects provided by normal and shear stresses, can have high values, close to those for which the structure can reach to the failure point. If the effects of erosion and clashes with foreign bodies are added, the structure of the blade may lose its integrity. Considering both the complex shape of the blade and internal structure used, the mechanical behavior of the blade, such as the rigidity and resistance along the length of the blade, are usually determined with some uncertainty. This paper presents the results obtained in the non-destructive tests at static torsion of a scalable wind turbine blade. The objective of the paper was to determine the variation of the equivalent stress in the most stressed points of the blade, in relation to the torques applied. To determine the points with the highest stress, a finite element analysis was performed on the scalable wind turbine blade. Electrotensiometric transducers were mounted at different points of the blade, determining the main stresses in the respective points, as well as their variation during the torsion test, by subsequent calculations. The determinations were performed by applying the torque in both senses, in relation to the blade axis, thus concluding the values of the equivalent stress in the two cases

Electromagnetic configurable architectures for assessment of Carbon Fiber Reinforced Plastics

Carbon Fiber Reinforced Plastics are used in most wide domains due their low density, lack of mechanical fatigue phenomena and high strength–to weight ratio. From electromagnetic point of view, Carbon Fiber Reinforced Plastics structure represents an inhomogeneous structure of electric conductive fibers embedded into a dielectric material, thus an electromagnetic configurable architecture can be used to evaluate above mentioned defects. The paper proposes a special sensor, send receiver type and the obtaining of electromagnetic image by post-processing each coil signals in each point of scanning, using a sub-encoding image reconstruction algorithm and super-resolution procedures. The layout of fibers can be detected interrogating only diagonal reception coils

Electromagnetic configurable architectures for assessment of Carbon Fiber Reinforced Plastics

Carbon Fiber Reinforced Plastics are used in most wide domains due their low density, lack of mechanical fatigue phenomena and high strength–to weight ratio. From electromagnetic point of view, Carbon Fiber Reinforced Plastics structure represents an inhomogeneous structure of electric conductive fibers embedded into a dielectric material, thus an electromagnetic configurable architecture can be used to evaluate above mentioned defects. The paper proposes a special sensor, send receiver type and the obtaining of electromagnetic image by post-processing each coil signals in each point of scanning, using a sub-encoding image reconstruction algorithm and super-resolution procedures. The layout of fibers can be detected interrogating only diagonal reception coils