Multi-Physics-Based Intelligence Sensing System for Fatigue and Fastener Crack Detection in Multi-Layer structures

ABSTRACT:In the past several years, Structural Health Monitoring (SHM) has emerged from the research environment into initial applications in a wide variety of fields. Before SHM systems can be implemented in an operational environment, there is a need for new methods and procedures to compensate for uncertainty in SHM systems arising from a variety of reasons, including component geometry, loading and boundary condition changes, aging effects etc. In this program Acellent proposes to develop an innovative Multi-Physics-Based Intelligence Sensing System for Fatigue and Fastener Crack Detection in Multi-Layer structures to address the uncertainities for detection. The goal will be to accurately detect, locate and characterize fatigue cracks as well as corner cracks originating from fastener holes in multi-layer structures. Phase I will focus on defining the overall SHM framework and developing methodologies to compensate for variability in an operational environment. The methods used will be practical for real-world applications and be applicable for robust operation of the SHM system in austere flight/field environments with limited maintenance and low false call rates. The program will be supported by Boeing for future implementation on aircraft structures in concurrence with the U.S. Air Force Aircraft Structural Integrity Program (ASIP) requirements.BENEFIT:The largest and nearest-term impact areas for the technology are inaccessible areas in todays aircraft. Economic factors drive the need to keep these vehicles in-service for longer periods of time, often well beyond their designed service life. As these structures age, there is an increasing need for inspection to ensure public safety, ensure combat readiness and schedule maintenance effectively. The high cost of owning and operating these systems provides incentives for enhancing the means of evaluating and monitoring their structural integrity. The big challenge to this industry is that it must maintain a high standard of safety with its fleet in an economic environment with cost-effectiveness that is intensely competitive. With the growing number of older aircraft in service, the business case for Structural Health Monitoring (SHM) retrofit applications is increasingly gaining more and more momentum. Retrofit applications focused on monitoring age-related degradation parameters like fatigue, corrosion and delamination are a key target of SHM. The target SHM technology is lightweight, easy to install and simple to use. The emphasis is not only on the development of further new SHM technologies, but also on testing the SHM systems robustness in representative environments to mature future service applications. The proposed system could potentially lead to significant savings in maintenance costs for aircraft (30-90% depending on application), can enhance the reliability of the structures and improve their efficiency, safety, and readiness. The proposed innovative, integrated inspection system, can efficiently and economically manage structural inspection data for the fleets of aging U.S. Air Force aircraft. The proposed work will be conducted in close collaboration with companies such as Boeing to ensure that this work will be directly beneficial to them.