Integration of Technologies for Structural Integrity Assessment of Critical Safety-of-Flight Components, 18-R9844

Printer Friendly Version

Principal Investigators
Dale Cope
Clint Thwing
Kurt Schrader
Kristopher Kozak

Inclusive Dates:  07/01/08 – Current

Background - Government agencies and the commercial aviation industry are placing greater emphasis on the need for technology development to help assure the safety and operational readiness of the nation's military and civilian aircraft fleets. This greater emphasis is reflected in the aviation safety goals in the National Plan for Aeronautics Research and Development, which include the development of technologies to reduce accidents and incidents through enhanced vehicle design, structure and subsystems. A near-term objective of this goal is the development of vehicle health management systems to determine the state of degradation for aircraft subsystems. This objective is shared by the Air Vehicles Directorate of the Air Force Research Laboratory (AFRL) and the Aeronautics Research Mission Directorate of the National Aeronautics and Space Administration (NASA). Both directorates have major research programs in integrated vehicle health management.

Approach - In support of the National Plan, Southwest Research Institute (SwRI) is investigating the feasibility of integrating remote sensing technology with probability of failure analyses into a monitoring system capable of assessing the structural integrity of critical airframe components. The project focuses on demonstrating the viability of remote sensing to discern structural flaw nucleation and growth along with integrating the sensor data with a software reasoner module capable of performing near real-time risk analysis based on actual usage to assess the integrity of the critical structural component. The project will demonstrate this integration of technologies on a complicated structural component that has limited accessibility with realistic loading. As illustrated in attached flowchart, the project employs the following technical approach for the development for the airframe health management system:

  • Identify the structural item of interest and its relevant failure modes
  • Characterize the critical failure modes that result in system degradation
  • Design a sensor system to capture degradation mechanisms
  • Develop a software reasoner module to assess the current state of the component based on initial sensor output along with real-time and updated sensor output
  • Predict remaining capability based on interpretation of sensor data and assumed future operating conditions.

Accomplishments - For this project, SwRI researchers are drawing on their extensive knowledge in aircraft usage and structural loads for the T-38 aircraft along with their expertise in advanced sensor technology. The airframe component chosen for this study is the T-38 fuselage longeron highlighted in the attached illustration. The longeron has been shown to be fatigue critical through full-scale testing. Its fatigue critical locations have limited accessibility and are difficult to inspect using conventional techniques. The Air Force has provided an upper fuselage section containing the longeron for use in the research project, and SwRI is currently adapting the fuselage section for use as a fatigue test article. The researchers are formulating an approach to incorporate emerging sensor technology, such as the magnetostrictive sensor (MsS) technology developed by SwRI, into the design of a monitoring system for detecting, localizing, and assessing damage in the fuselage longeron. SwRI researchers are developing a software reasoner module that integrates aircraft usage data, structural loads data, and damage sensor data with model-based and data-driven techniques for detecting incipient damage and assessing local/global structural integrity of critical airframe components. Successful completion of the project will demonstrate the feasibility of an integrated structural health monitoring system by employing the system during the fatigue testing of the T-38 fuselage section, which contains the longeron. Assessment of the system design will evaluate the ability to detect and localize damage in the longeron while assessing the likelihood of failure based on actual current usage, current damage state, and assumed future operating condition.

2008 Program Home