First experiments for the diagnosis and thermophysical sampling using pulsed IR thermography from unmanned aerial vehicle (UAV)

Abstract

Infrared (IR) thermography is a control method widely used for building diagnosis to investigate structural blemishes and thermal heat losses. Usually, collecting the thermal heat flux naturally emitted by a studied surface via an IR camera, we obtain critical information regarding its structure through passive infrared thermography. The thermogram can then reveal an abnormal variation of the heat flux and highlight a defection. However, on building applications in the case of Non Destructive Testing and Energy Consumption Investigation, spare control often only emits no significant heat due to the high thermal inertia materials that are often used. To overcome such problem, active impulse infrared thermography is an interesting alternative method, since we can access to information not provided spontaneously by analyzing the passive thermal emission of the surface. Hence, in this work, the front face flash method is proposed in order to analyse the subsurface thermal properties. Furthermore, it is proposed to couple impulse IR thermography with a stable Unmanned Aircraft Systems (UAV) to record and analyse the transient temperature response during convenient time duration. Preliminary results and several practical problems for the implementation of such experimental device are given and discussed here.

Autonomous systems thermographic NDT of composite structures

“…There are results from a UAV NDT test which was used for a civil application, the results indicated an excess of noise from the UAV, since this flight was performed without the use of GPS, this affected the results and the noise was due to the stabilisation problem. It is necessary to perform pixel by pixel treatment in addition to the standard average signal study [11]. To do this, the IR camera needs to be as static as possible, GPS or other localisation techniques can be used to compensate for any stability problems.…”

“…The experiment will consist of inspecting three different specimens to search for defects but more specifically concentrating on kissing bond defects [5]. The three inspected specimens are all composite material with artificial defects (see fig.10, 11,12,13) ➢ Specimen N-D-F4P is composed of one layer of adhesive sandwiched by two layers of adherent (carbon fiber) and contains no defect, it was purposely used for reference only. ➢ Specimen W-DA-F4 is similar to N-D-F4P but with an adhesive film release semi-circular ("thumb nail") shape defect, simulating a kissing bond defect.…”

“…A liquid paint substance is added to a metallic wing panel and a UAV equipped with a UV light inspected the aircraft in a dark room, the primary objective is to execute the algorithms in order to display, classify and log defects [10]. IRT is a fast-non-contact method and is wellsuited for testing large areas of complex geometry [11]. Nevertheless, the traditional thermographic systems are bulky and inconvenient for use on many applications.…”

On‐site inspection of potential defects in wind turbine rotor blades with thermography

“…Its potential lies in the fast assessment of large inspection areas. It is a contact‐free method which can be used from larger distances, for example, from an aircraft …”

“…It is a contact-free method which can be used from larger distances, for example, from an aircraft. 8,9 In the framework of the research project IKARUS, we are validating the potential of thermographic methods for the inspection of rotor blades of offshore wind turbines performed from an aircraft such as a helicopter ('IKARUS' stands for Infrared-Kamera technology for the non-contact Analysis of Rotor blades under Open-Sea-Conditions). Interim results were presented before, whereas different aspects and influencing factors concerning thermography on wind turbine rotor blades were discussed.…”