College of Engineering News • Iowa State University

Iowa State, Air Force Research Laboratory develop real-time structural health monitoring technology

Iowa State University (ISU) and Air Force Research Laboratory Munitions Directorate (AFRL/RW) explore the fastest methods of detecting damage to next-generation systems

In January, researchers at Iowa State University and the Air Force Research Laboratory Munitions Directorate began collaboration to develop the fastest methods of conducting high-rate state estimation for complex systems, including aircraft, spacecraft and weapon systems.

The joint $1.2M project is titled “Novel variable input observer for high-rate state estimation.” Funded by the Air Force Office of Scientific Research (AFOSR), this project looks at how structures exposed to fast and severe damage can be monitored in real-time.

“We are studying algorithms to conduct state estimation, trying to answer the question ‘how fast can we estimate a change in the system?’” said Dr. Simon Laflamme, the university’s project manager and an associate professor of civil, construction and environmental engineering at Iowa State.

“Modern engineering is producing a growing number of high-rate dynamic systems …,” Laflamme said. “From these systems arise several opportunities, including a high potential to reduce injuries and save lives. This could be done through high-rate state estimation by identifying a problem before it endangers a system, and its users could take corrective actions on time.”

High-rate state estimation is the quick analysis of structural integrity. For example, if an object strikes an aircraft, high-rate state estimation is the process by which the aircraft’s structural health monitoring (SHM) technology senses any changes or damages. Systems that are subject to this sort of severe damage are high-rate systems. Current technology limits the calculation of high-rate state estimation, as many structural health systems are unable to monitor structures on a microsecond time scale. But in recent years, structural health monitoring in real-time has become increasingly important as a guard against threats.

“Imagine that one could deploy anti-blast measures to protect a building against terrorism,” Laflamme said. “The detection of the blast wave, before it hits the building, would be critical in ensuring the on-time deployment of such measures.”

In November, the AFLR Munitions Directorate signed an educational partnership agreement, or EPA, with Iowa State. That agreement encourages collaboration between the university and the AFRL on various research projects, including this current project. Laflamme and AFRL engineers, of which the AFOSR is a component, will focus on two research techniques for the state estimation project.

“Iowa State will study data-based techniques, which means that we purely rely on sensor measurements to try to detect and quantify changes (the variable input observer),” Laflamme explained. “AFRL will study model-based techniques, which means that we start with a physical description of what the system is and detect and quantify changes through the alteration of the physical description.”

Throughout the research, engineers will work to construct a high-rate state estimation algorithm. When integrated with SHM technology, the algorithm would allow for analysis of changes or damages in real-time. Ultimately, the research will …

  • Produce an algorithm that will enable real-time state estimation
  • Develop a numerical model for simulations and performance metrics
  • Identify opportunities in which the algorithm can be utilized by high-speed complex structures
  • Recognize any limitations to real-time state estimation processes

This project began on January 15 and will continue through January 2020.

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