Health monitoring and damage prognosis of aircraft composite structures

点击翻译按钮获取中文摘要

Health monitoring through adequate prediction of the remaining useful life of composite structures is a major area of interest for the aerospace community where the growing maintenance costs, estimated to $10 billion worldwide annually, can reduce their economic life. The objective of the proposed research program is to design and manufacture advanced composites integrated with fiber optic sensors to monitor the manufacturing process and to use the same sensor network to develop a damage prognostic approach to gradually replace current schedule-based maintenance tasks, where components are inspected after a pre-established number of cycles, by condition-based maintenance, where components are maintained prior to attaining an insufficient remaining useful life. The current systems and technologies available for monitoring the health of the aircraft components are mostly based on load monitoring systems that determine flight parameters, and enable conclusions to be drawn concerning the load levels occurred during the flight, or scheduled maintenance by means of small area scanning processes such as radiography, eddy currents, ultrasonic or other appropriate methods. The existing methods are time consuming and cost intensive. Therefore, the availability of a non-destructive evaluation technology, which makes the structural health assessment an integral part of the aircraft components, known as Structural Health Monitoring, is crucial in terms of reducing time and cost associated with maintaining reliability of components. SHM is an emerging technology, dealing with the development of techniques and systems for the continuous monitoring, inspection and damage detection of structures, with minimum labor involvement. The SHM focuses on finding answers to the very critical questions on: (i) damage existence in a structure and its type, (ii) whether the damage is local or global (e.g., a large isolated crack or many small defects distributed in the material), (iii) the location of the damage whether the damage is in the material or in the joints and connections (or both), and (iv) finally find out whether the structure is likely to fail due to the presence of damage.