6533b854fe1ef96bd12ae071

RESEARCH PRODUCT

Implementation of a fast and low cost IR-NDT technique by means of a Square Pulse modulated Lock-In Thermography

Giuseppe Pitarresi

subject

Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di MacchineInfrared Thermography NDT Lock In Thermograpghy Glass Fibre Reinforced

description

This work describes the development of an IR-NDT procedure based on a lock-in signal treatment in the frequency domain to obtain phase-contrast defect signatures. Heat stimulation is obtained by periodically shattering a common low-power halogen lamp. The delivered heat is then modulated as a train of square waves with multi-frequency harmonic content. The proposed lock-in algorithm is able to selectively retrieve phase and amplitude information at various frequencies of the acquired temperature, acting also as a narrow band filter to improve defect-signature to noise ratio. The procedure is implemented and evaluated by means of low cost IR equipment to investigate artificially defected thick Glass Reinforced Plastic (GRP) panels.

https://doi.org/10.21611/qirt.2012.343