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San Juan de la Rambla, Spain

Usamentiaga R.,University of Oviedo | Venegas P.,Aeronautical Technology Center | Guerediaga J.,Aeronautical Technology Center | Vega L.,Aeronautical Technology Center | Lopez I.,Aeronautical Technology Center
Infrared Physics and Technology | Year: 2013

Accidental impacts can severely reduce the structural strength and stability of composite materials, which can lead to severe consequences due to the degradation of the mechanical properties of components designed to perform for decades. Because accidental impacts are difficult to avoid, robust and reliable inspection methods to detect impact damage are required. Many methods have been proposed recently. However, most of them require an experienced technician to analyze the data, which leads to a significant decrease in manufacturing productivity. This work proposes a method to automatically detect impact damage in carbon fiber composites using active thermography. The proposed system detects defects caused by impact damage in the infrared images without human intervention. Impact damage detection is performed using a robust method based on an active thermographic inspection. Thermographic data is preprocessed to improve signal-to-noise ratio and to remove non-uniform background caused by non-uniform heating. Then, peaks and edges are identified and clustered, and regions corresponding to impact damage are detected. The proposed procedure has been applied to three specimens that contain 6 and 12 plies, different types of cores, and damage caused by energies from 6 J to 50 J. All defects are detected correctly. © 2013 Elsevier B.V. All rights reserved. Source


Usamentiaga R.,University of Oviedo | Venegas P.,Aeronautical Technology Center | Guerediaga J.,Aeronautical Technology Center | Vega L.,Aeronautical Technology Center | Lopez I.,Aeronautical Technology Center
NDT and E International | Year: 2013

The use of composite materials in the industry has increased in the past few decades due to their high strength and stiffness to weight ratios. However, composite materials have a serious weakness: their sensitivity to impact damage. This work proposes a method to automatically characterize impact damage in carbon fiber composites using active thermography. Shape and amplitude features are extracted from the defects detected using image processing. The analysis of these features provides relevant conclusions about their relation to the impact energy, and the influence of number of plies and the type of core of the composite. Finally, a classifier based on neural networks is proposed to automatically characterize the detected defects caused by impact damage according to impact energy. Tests carried out over several specimens that contain impact damage of different energies show excellent performance for the classifier. © 2012 Elsevier Ltd. Source


Usamentiaga R.,University of Oviedo | Venegas P.,Aeronautical Technology Center | Guerediaga J.,Aeronautical Technology Center | Vega L.,Aeronautical Technology Center | Lopez I.,Aeronautical Technology Center
Infrared Physics and Technology | Year: 2012

The aerospace industry is in constant need of ever-more efficient inspection methods for quality control. Product inspection is also essential to maintain the safe operation of aircraft components designed to perform for decades. This paper proposes a method for non-destructive inspection of drilled holes in reinforced honeycomb sandwich panels. Honeycomb sandwich panels are extensively employed in the aerospace industry due to their high strength and stiffness to weight ratios. In order to attach additional structures to them, panels are reinforced by filling honeycomb cells and drilling holes into the reinforced areas. The proposed procedure is designed to detect the position of the holes within the reinforced area and to provide a robust measurement of the distance between each hole and the boundary of the reinforced area. The result is a fast, safe and clean inspection method for drilled holes in reinforced honeycomb sandwich panels that can be used to robustly assess a possible displacement of the hole from the center of the reinforced area, which could have serious consequences. The proposed method is based on active infrared thermography, and uses state of the art methods for infrared image processing, including signal-to-nose ratio enhancement, hole detection and segmentation. Tests and comparison with X-ray inspections indicate that the proposed system meets production needs. Source


Usamentiaga R.,University of Oviedo | Venegas P.,Aeronautical Technology Center | Guerediaga J.,Aeronautical Technology Center | Vega L.,Aeronautical Technology Center | And 2 more authors.
Sensors (Basel, Switzerland) | Year: 2014

The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed. Source

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