Effects of bleeder cloth impressions on the use of polar backscatter to detect porosityThe influence of the nature of the composite's surface on ultrasonic polar backscatter measurements for detecting and characterizing porosity in composite laminates is studied, focusing on the effects of bleeder cloth impressions noted by Bar-Cohen (1987). The results indicate that the presence of the bleeder cloth impressions substantially influences the degree of anisotropy. It is found that, for relatively thin samples in which selective time gating is not feasible, the state of the insonified surface and the state of the back surface both influence the received signal.
Document ID
19890029139
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Handley, S. M. (NASA Langley Research Center Hampton, VA, United States)
Miller, J. G. (Washington University Saint Louis, MO, United States)
Madaras, Eric I. (NASA Langley Research Center Hampton, VA, United States)