Jean-Michel Roche

Common tools for quantitative time-resolved pulse and step-heating thermography – part I: theoretical basis

Several advanced pre- and post-processing tools have been developed over the last two decades, to enhance the performance of time-resolved pulse thermography, in terms of defect detection and characterisation. Two of the most efficient techniques are the Thermographic Signal Reconstruction, proposed in 2001, including a recent development based on the use of the polynomial coefficient images proposed in 2014, and the early detection of emerging contrast, proposed in 1994. The stake of this work is to show how these tools, commonly used for pulse-heating, can be applied to step-heating. The work was divided in two parts: the theoretical and analytic study is reported in the present article; the matching experimental results are discussed in a second, separate article.

Common tools for quantitative pulse and step-heating thermography – part II: experimental investigation

Several advanced pre- and post-processing tools have been developed over the last two decades, to enhance the performances of pulse thermography, in terms of defect detection and characterisation. Two of the most efficient techniques are the Thermographic Signal Reconstruction, including a recent development using the polynomial coefficient images, and the early detection. This work, which shows how these tools, commonly used for pulse-heating, are complementary and applicable to step-heating, is in two parts: the first one, reported in a companion article, is dedicated to the theoretical and analytical demonstration; the second one, reported here, is the matching experimental investigation.

Investigation of multiple cracking in glass/epoxy 2D woven composites by vibrothermography

An experimental study about the application of vibrothermography for the investigation of multiple micro-cracking in woven composites is here reported. The material is first damaged during tensile loading tests in order to have samples that present increasingly damaged states. The goal of the study is to evaluate the sensitivity of the vibrothermographic effect to crack density. A linear correlation trend is observed on the tested samples between the measured heating during mechanical excitation and the crack density. A linear correlation trend is also observed between the heating and the loss of in mechanical property of the material (in this case the Young modulus).