Delamination analysis after carbon/epoxy plate drilling

Abstract

Drilling of carbon fibre reinforced plates CFRP causes typical damages such as delamination and others. These damages, that cannot be visually detected, can cause the premature collapse of structures. Damage assessment is usually carried out using non-destructive inspections like radiography and ultrasonic C-scan. Damage extent can be evaluated by the use of damage criteria. One of them delamination factor was proposed by Chen, establishing a ratio between the maximum damaged diameter and the hole nominal diameter. Another one damage ratio was presented by Mehta comparing the damaged area with the hole average area. Both ratios allow for comparison between different drilling conditions. In this paper the images obtained are processed and analyzed using standard techniques from Computational Vision together with a processing platform already developed. An experimental evaluation using radiographic and C-scan images to obtain the referred ratios will be presented.