This work aims to compare quantitatively different nondestructive testing (NDT) techniques and data fusion features for the evaluation of adhesive bonding quality. Adhesively bonded composite-epoxy single-lap joints have been investigated with advanced ultrasonic nondestructive testing and induction thermography. Bonded structures with artificial debonding defects in three different case studies have been investigated: debonding with release film inclusion, debonding with brass film-large, debonding with brass film-small. After completing preprocessing of the data for data fusion, the feature matrices, depending on the interface reflection peak-to-peak amplitude and the principal component analysis, have been extracted from ultrasonic and thermography inspection results, respectively. The obtained feature matrices have been used as the source in basic (average, difference, weighted average, Hadamard product) and statistical (Dempster–Shafer rule of combination) data fusion algorithms. The defect detection performances of advanced nondestructive testing techniques, in addition to data fusion algorithms have been evaluated quantitatively by receiver operating characteristics. In conclusion, it is shown that data fusion can increase the detectability of artificial debonding in single-lap joints.

The aim of this paper is to simulate a large power brushless synchronous generator used for large turbo-alternator brushless excitation systems under conditions of saturation and rotating rectifier diode failures. A reluctance network coupled with electric circuits and power electronic components integrating the movement and nonlinearities of materials has been developed. The approach achieves good compromise between accuracy and computing time for the complete analysis of a 39 phase machine with 117 teeth and 22 poles, and 78 diodes in the associated rectifier bridge. Our model is validated by comparison with experimental measurements and numerical simulation by a finite element package. For the simulations presented, a gain in computation time of 800 can be obtained compared with a finite element model. Different results are calculated for healthy and faulty states to study the impact of open diode block failure. Simulation results show that open diode failures have little effect on the rectified output voltage, but the current through diodes and protection fuses increases. The currents in armature phase coil are very affected due to failures. A flux sensor coil can be placed on the stator pole to capture the impact of failures. The harmonic content of the pole flux can be used to monitor and detect diode failures.

In this paper, a 3-D modeling of a thermo inductive nondestructing testing (NDT) technique applied to carbon fiber reinforced polymer (CFRP) composite is presented. A multiscale approach is used to calculate the electromagnetic and thermal field distribution. The relevance of the technique is then discussed for different positions of flaws and the optimal frequency is estimated.

Numerical simulations by means of finite elements are used to investigate the capacities of the induction thermography technique for the characterization of electrical conductivities of unidirectional Carbon Fiber Reinforced Polymer (CFRP) materials. A coupled electromagnetic-thermal model is presented using hexahedral elements to deal with thin region of fully anisotropic physical properties. Eddy-current problem is solved using the T – Ω formulation to deduce heat source density power. Transient thermal problem is solved with fixed time step. An error minimization-based method is presented to identify the electrical resistivity of unidirectional CFRP from induction thermography measurement.

Using a 3D finite elements simulation tool, a study on the flaw detection capacity of the non destructive testing (NDT) induction thermography (IT) technique for laminated carbon fiber reinforced polymers (CFRP) composites is presented. Delamination and fiber rupture flaw occurring at the elementary-ply scale are considered. In order to reduce the impact of measurement noise on the flaw detectability, several signal processing techniques are proposed.

This paper discusses the possible non-destructive testing (NDT) techniques for a novel bonding quality evaluation technique based on comparison of different inspection methodologies. The goal of this paper is to guide a way for bonding quality evaluation with high reliability by comparing different NDT techniques including ultrasonic, electromagnetic, and thermography. The advantages and limitations of each different NDT technique have been reported systematically. Two case studies have been investigated with two different NDT techniques, namely ultrasonic and induction thermography. The results suggested the limitations and advantages of NDT techniques. In order to compensate the limitations of each technique, data fusion of the selected techniques is proposed.