Novel system detects and assesses damage of aircraft composites
Currently, NDT is exploited in four levels of 'checks' (A-D). A checks are done every 500-800 flight hours, but they only require an overnight out of service to complete. D checks are only done every 5-6 years but require up to 3 months to complete. In addition, all these checks require a large hangar and dedicated NDT facilities. Ten partners from six European countries came together on the TRACE-IT (An advanced structural integrity system for air transport composites using NDT evaluation and damage tolerance methods) project to address the pressing need for more efficient and reliable damage inspection. The project focused on C and D checks as they consume the most time, money and personnel. Scientists developed a comprehensive mobile inspection and assessment technique for any type of composite structure. The inspection system exploits an ultrasonic phased array (PA) method attached to a mobile manipulating system that accommodates both automated and manual inspections. The manipulating system is lightweight and can inspect flat and curved surfaces, moving in vertical and upside-down positions. Data from the PA inspection is fed into a damage tolerance numerical analysis algorithm. Outcomes consist of the state of structural integrity, criticality of damage, estimation of remaining life, and whether a substitute or repair is required. A software application accompanies the inspection system, responsible for the scanner control, position mapping and communication with the ultrasonic module for sharing the probe coordinates. For defect screening, researchers used a linear PA probe consisting of the scanner itself, an electronic control unit and the air control unit for automatic inspections, and a trolley wedge for manual inspections. TRACE-IT's automated inspection and assessment platform should significantly reduce the life-cycle cost of aircraft components while improving the safety and reliability of air transport. Given the current economic climate in Europe, the technology will provide welcome relief to the aerospace industry and potentially to passengers benefiting from reduced fares.
Keywords
Aircraft, composites, non-destructive testing, damage tolerance, TRACE-IT, structural integrity
