Square Heating Applied to Shearography and Active Infrared Thermography Measurements Coupling: From Feasibility Test in Laboratory to Numerical Study of Pultruded CFRP Plates Glued on Concrete Specimen

Abstract

International audienceThis paper investigates thermography and shearography couplings, using feasibility trials and numerical simulations, for non-destructive control evaluations of bonding of carbon fiber-reinforced polymer plates glued over concrete structures. Those are well-known methods in non-destructive testing (NDT) applied to civil engineering, but in this context, they are seen as paired because they use the same excitation source: square-pulsed optical heating. Furthermore, because both methods are based on different properties, the detection of defects is optimised regardless of its nature or type. The combination of the methods allows the measurement of a thermal as well as a thermomechanical response from the structure at the same time. A quick review of those methods and their respective advantage and inconvenient is mentioned. An in-depth study of the interpretation of the thermal and mechanical responses is carried out in relation to the thermal excitation. Then, the thought process behind the conception of the finite element model and its limitation is discussed. The experimental setup, used for feasibility testing, is described as well as a thorough analysis of the experimental and simulated results. Finally, the pairing of both methods is discussed regarding the evaluation of the bond quality, as well as the similitude of the sample and its numerical model

Pulse-heating infrared thermography inspection of bonding defects on carbon fiber reinforced polymer composites

“…16,17 Recently, scholars have used pulse infrared thermography inspection to conduct a series of experimental and numerical simulation studies on the interface of FRP-reinforced concrete structure, including the heating method of FRP defect detection, the effect of thermal excitation energy on defect detection, the influence of environment on defect detection, the location of FRP layer defect, the defect detection of FRP components in the process of static loading, composite defect detection under fatigue loading, defect detection in actual FRP structural engineering and other aspects. [18][19][20][21][22][23][24][25][26] However, applications of infrared thermography to concrete structures are at an early stage of development and further experimental and numerical studies are needed.…”

Study of an optimal heating duration indicator for square pulsed thermography applied to CFRP gluing quality control

“…During previous works, square pulsed thermography was used to carry out non destructive testing of bonding quality of CFRP glued on civil engineering structures during reinforcement operations [1,2]. The use of such wave form excitation was motivated by "on-site" requirements, but also by measurements duration, number of composite layers to test, depth of possible faulting areas versus temperature elevation allowed at composite level according to inner heat diffusion.…”