PENETRATION DEPTH LIMITS OF ACTIVE THERMOGRAPHY FOR DETECTION OF IMPACT DAMAGE IN CARBON FIBRE COMPOSITES

摘要

This paper outlines an investigation of the penetration depth limits of two active thermographic inspection techniques, flash thermography and sonic thermography, for quantitative sizing of barely visible impact damage in 4 mm thick carbon fibre composite plate. The impact damage size and depth was first determined using phased array ultrasonic testing. Thermographic inspections were then carried out and the damage size measured from processed thermal signatures compared to the C-scan results. Size estimates obtained from sonic thermography are shown to compare favourably with the C-scan results, indicating full through-thickness penetration for this method. The size estimates obtained from flash thermography indicated only partial thickness penetration.