A comprehensive study of ultrasonic detection and damage quantification of barely visible impact damages in a carbon fiber reinforced polymer composite material

Abstract This work investigates detection and evaluation of barely visible impact damage (BVID) on a carbon fiber reinforced polymer composite using non‐destructive evaluation. Specifically, this paper presents a novel method to analyze full waveform from ultrasonic data captured from a new field portable inspection station. Forty‐eight samples are impacted between 8 and 16 J representing a spectrum of surface damage below the visual threshold to barely visible surface damage. The samples are conditioned at cold and dry (5°C and 10%RH) to hot and wet (50°C and 90%RH) environmental conditions prior to inspection. Data collection for ultrasonic inspection is performed on a novel portable inspection system outside of an immersion tank, and the captured full waveform data is analyzed. The waveforms are analyzed using a new automated analysis approach presented in the current manuscript, and the effective diameter of the subsurface damage as a function of depth is extracted from the data set. The extracted three‐dimensional damage zone from the analysis of the ultrasound data shows damage increasing from the surface that is at or below the visual inspection threshold to a circular like damage zone with an effective diameter subsurface that is more than 20 mm. These damage zones are compared to the analyzed μCT data sets, and the average error is nominally 1 mm in characterizing the effective diameter at any depth. There is little correlation between the error and the impact energy or the environmental conditions studied, with the error ranging from 4% to 6% over the samples investigated. Highlights Out of immersion tank, field‐portable ultrasound inspection station, to detect BVID. Automated procedure to characterize three dimensionally the damage from a barely visible impact damage event. Sensitivity to environmental conditioning is investigated for its impact on inspections. Results validated with x‐ray CT with a typical accuracy of 1.32 mm.