The Detection and Characterization of Impact Damage to Carbon Fiber Composites With Thermal Shearography

Newman, John; Level X NDT; United Kingdom

Buckley, J.M.; Level X NDT; United Kingdom
Newman, J.W.; Laser Technology Inc.; United Kingdom

ID: ECNDT-0572-2018
Session: Composite General 1
Room: G1
Date: 2018-06-11
Time: 14:10 - 14:30

Shearography is a full field NDT technique using an imaging interferometric capable of quantitative measurement of surface deformations as small as 2 nm. Using thermal stressing as the loading mechanism shearography has demonstrated exceptional sensitivity to impact damage to carbon fiber laminates, honeycomb sandwich panels and composite over wrapped pressure vessels (COPV). This paper summarizes an investigation of shearography for impact damage in these three structure types and compares results where applicable with UT C-Scan 1MHz TTU and the BondMaster in Pitch Catch with 5629 PHV Probe. The results demonstrate shearography can have a sensitivity equal or better than C-Scan for the components and materials evaluated.

First developed in the mid 1980’s, shearography has been highly developed by the authors’ team for nondestructive testing of aerospace, marine, automotive and architectural composites. This paper will also provide by way of background:
• Shearography NDT Theory
• Shearography NDT for delamination, disbonds cracks and wrinkled fibers,
• Applications: aerospace composites, launch vehicle and spacecraft structures, marine composites, concrete and steel crack detection