About This Project

An aging structure needs to be investigated periodically to prevent catastrophic failure. Crack development is one of the major concern for a structure in service. Early crack detection prevents catastrophic failure and can provide safety. When crack grows, it releases energy as acoustic emission (AE) waveform. AE waveform can be used to diagnose the state of the structure. Here a novel method is proposed to extract crack growth information from AE waveform using energy approach.

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What is the context of this research?

This research focuses on developing an efficient and cost effective approach for in-situ crack detection. A successful crack detection procedure depends on the appropriate methodology to implement. In this proposal, a novel method is proposed to extract AE source (crack related) information using energy approach. The objective is to characterize the source from a crack growth by analyzing the AE signal. According to the new concepts if one can characterize the source, it will provide the energy released information from the crack, and that can be correlated directly with the crack growth. This crack detection technique allows (a) optimal use of the structure (b) a minimized downtime (c) the avoidance of catastrophic failures (d) reduce the maintenance services.

What is the significance of this project?

In practical applications, incremental crack growth in a structure provides AE waveform that can be recorded by a sensor attached to the structure. Periodic investigation of AE waveform can give the insight information of the crack growth. However, extracting AE source feature (crack-related information) from a recorded AE waveform is always challenging, and the underlying physics is much more complicated. This new technique can be used to extract crack growth information efficiently and accurately. Therefore, this research would be useful for early crack detection and preventing catastrophic failure with minimal effort and cost. The outcome of this project could directly be applied to the SHM applications of aerospace, defense, civil infrastructure, etc.

What are the goals of the project?

For implementing the new concept, an AE experiment will be designed to measure the acoustic emissions from the fatigue crack growth. The AE sensor will be attached to the specimen to capture the AE signals. The AE instruments record the signals as AE waveforms. An inverse algorithm will be developed to characterize the source from AE signal. In inverse algorithm, the source parameters will be calculated. Source parameters provide the insight information about the crack growth in a structure. Once source parameters from AE signal is obtained then the crack growth rate can be determined. A forward problem will also be solved to simulate the AE guided wave using the released energy calculated from experiments and then the simulated signal will be compared to the experimental signal.