Autonomous systems thermographic NDT of composite structures

Abstract

Transient thermography is a method used successfully in the evaluation of composite materials and aerospace structures. It has the capacity to deliver both qualitative and quantitative results about hidden defects or features in a composite structure. Aircraft must undergo routine maintenanceinspection to check for any critical damage and thus to ensure its safety. This work aims to address the challenge of NDT automated inspection and improve the defects' detection by suggesting an autonomous thermographic imaging approach using a UAV (Unmanned Aerial Vehicle) active thermographic system. The concept of active thermography is discussed and presented in the inspection of aircraft CFRP panels along with the mission planning for aerial inspection using the UAV for real time inspection. Results indicate that the suggested approach could significantly reduce the inspection time, cost, and workload, whilst potentially increase the probability of detection of defects on aircraft composites.

Application of NDT thermographic imaging of aerospace structures

“…Plastic/Elastic deformation for a composite is very limited as the resultant energy is frequently absorbed in creating large areas of fracture, which will affect the performance of the material due to the reduction in both strength and stiffness [15]. During composite manufacturing, it is possible for the material to be damaged due to the complexity of the manufacturing process [16] [5]. Figure 1 shows the composition of a composite material.…”

“…Due to the increased demand of CFRP, it has subsequently caused rapid large-scale manufacturing. For instance, Airbus estimates its Carbon Fiber demand to soar to around 20,000 tons by the year 2020 (see figure 3, right) [7] [5]. [15].…”

“…Infrared Thermography (IRT) is predominately being used to detect subsurface defects in a plethora of structural elements and mechanical systems that consist of a wide range of materials [3]. It is one of the newest non-destructive technologies and has proven to provide substantial improvements in performance as well as good cost savings, allowing more frequent maintenance with minimal manpower [4] [5].…”

“…It is estimated that there are more than 120,000 inspectors worldwide and the global NDT industry has an estimated turnover of 5.2 billion, it is an important and growing industry [9]. A cost-efficient NDT method, is needed to keep up with the manufacturing industry and ensure the safety of this complex material [10] [5].…”

“…Nevertheless, the traditional thermographic systems are bulky and inconvenient for use on many applications. Therefore, it is necessary to develop a more versatile thermographic system suitable to work in combination with UAV technology [5].…”