Dynamic Response of a Graphite/Epoxy Composite Plate

摘要

Graphite/epoxy composites have many advantages as aircraft structural materials and for this reason their use is becoming increasingly widespread. However, graphite/epoxy composites are susceptible to a wide range of damage. In particular, impact can cause a significant amount of delamination, even though the only external indication of damage may be a very small surface indentation. For this reason, this type of damage is often referred to as barely visible impact damage (BVID). the development of improved and more efficient means of detecting such damage is important. This paper investigates the potential for characterising the dynamic response of a graphite/epoxy composite plate to indicate the presence and possibly the location of BVID. A brief outline of vibrational analysis is given in section 2. The investigations included single point accelerometer response, time-averaged holographic interferometry and thermoelastic analysis. It was found that the detection of BVID using vibration analysis is complicated by the sensitivity of the analysis to boundary conditions and the means of excitation. Further investigation would require larger specimens to reduce the effects of boundary conditions.