Title :
Eddy Current Volume Heating Thermography and Phase Analysis for Imaging Characterization of Interface Delamination in CFRP
Author :
Yunze He ; Ruizhen Yang
Author_Institution :
Dept. of Instrum. Sci. & Technol., Nat. Univ. of Defense Technol., Changsha, China
Abstract :
Imaging inspection is highly demanded in the optimization of industry processes. Optical imaging inspection is not applicable for inside defects, while infrared (IR) imaging inspection can provide information about internal structure of objects. Eddy current thermography is an emerging IR imaging inspection technique for conductive materials or objects. This paper presents eddy current volume heating thermography (ECVHT) and phase analysis for delamination inspection in carbon fiber reinforced plastics (CFRPs) based on the previously proposed eddy current pulsed phase thermography (ECPPT). The proposed method has been verified through experimental studies under both transmission and reflection modes. After discrete Fourier transform (DFT) of temperature responses, the phasegram and phase spectra can be used to image and characterize interface delamination in CFRP due to elimination of nonuniform heating effect and carbon fiber structures. With the whole temperature response processed by DFT, carbon fiber structures and delamination can be differentiated due to periodic oscillation of phase spectra. With temperature response in cooling phase processed by DFT, some characteristic features can be extracted to construct the new phase images according to the shape of phase spectra. In all, using ECVHT and phase analysis, imaging characterization for delamination can get much better performance than conventional visible optical inspection system and eddy current pulsed thermography.
Keywords :
carbon fibre reinforced plastics; cooling; delamination; discrete Fourier transforms; infrared imaging; inspection; CFRP; DFT; ECVHT; Eddy current volume heating thermography; IR imaging inspection; carbon fiber reinforced plastics; carbon fiber structures; cooling phase; delamination inspection; discrete Fourier transform; eddy current pulsed phase thermography; eddy current pulsed thermography; eddy current volume heating thermography; imaging characterization; imaging inspection; industry processes; interface delamination; optical imaging inspection; phase analysis; phase images; reflection modes; transmission modes; visible optical inspection system; Cameras; Delamination; Eddy currents; Heating; Inspection; Reflection; Surface waves; Carbon fiber reinforced plastic; Carbon fiber reinforced plastic (CFRP); Delamination; Imaging inspection; Induction heating; Infrared imaging; Non-destructive testing; Phase analysis; Volume heating thermography (VHT); delamination; imaging inspection; induction heating; infrared (IR) imaging; nondestructive testing; phase analysis; volume heating thermography (VHT);
Journal_Title :
Industrial Informatics, IEEE Transactions on
DOI :
10.1109/TII.2015.2479856