Impact damage monitoring in composite plates: Fid-Bau Portal

Impact damage monitoring in composite plates

Shih, Frank J. / Benarjee, Sauvik / Mal, Ajit K.

This paper is concerned with the real-time detection of internal damage in composite structural components during impact using the far-field surface motion generated by these events. Impact tests are carried out on graphite epoxy composite plates using an instrumented impact testing system. Contact force and surface motion are measured at several locations on the plate surface. The far-field surface motions, both flexural and extensional waves in the composite plate, are modeled using both approximate and exact solution methods. Post-impact test were performed to determine the extent of internal damage caused by the impact load. Further research on the detection method can lead to the development of a viable impact monitoring system for composite aerospace structures using distributed sensors. The far-field waveforms from low velocity impacts on isotropic and anisotropic composite plates are studied. The sources from both impact surface load and internal delamination are measured and modeled. Delamination events are captured using an impact acoustic emission experiment where virtually unlimited event time can be recorded. It is demonstrated that acoustic emission waveform signals from impact events and the associated damage can be separated and quantified. Future work in this area needs to be focused on the modeling of distributed multiple sources, incorporating plate boundary, and improving the instrumentation by developing an active signal gain control for the transducers. Miniaturization of the acoustic sensors, the use of wireless networks that can receive data from remote locations would also greatly improve the applicability of the method to aircraft and aerospace structures.