R. Ecault, M. Boustie, L. Berthe, F. Touchard, L. Chocinski-Arnault, H. Voillaume and B. Campagne
The purpose of this paper is to develop a laser shock adhesion test (LASAT) and evaluate its ability to reveal various bond qualities of stuck carbon fiber reinforced polymer…
Abstract
Purpose
The purpose of this paper is to develop a laser shock adhesion test (LASAT) and evaluate its ability to reveal various bond qualities of stuck carbon fiber reinforced polymer (CFRP) industrial assemblies.
Design/methodology/approach
Four grades of adhesion were prepared by release agent contamination of CFRP prior to assembly. Laser shots were performed at different intensities on these samples.
Findings
To characterize and quantify the damage created by the propagation of shock waves in the bonded material, several diagnoses were used (confocal microscopy, ultra-sound inspection and cross-sections microscopy). These three post-mortem techniques are complementary and provide consistent results.
Originality/value
The combination of these diagnoses along with the LASAT technique provides relevant information on the bond quality in agreement with GIC values measured by the University of Patras.
Details
Keywords
Marko Jesenik, Anton Hamler, Miloš Beković and Mladen Trlep
The purpose of this paper is to find the geometry of a crack within a conductive plate and its parameters, on the basis of non-destructive testing, using eddy currents. The input…
Abstract
Purpose
The purpose of this paper is to find the geometry of a crack within a conductive plate and its parameters, on the basis of non-destructive testing, using eddy currents. The input data represents the measured values of magnetic flux density within the centre of the excitation coil.
Design/methodology/approach
The position of a crack can be determined by taking into consideration any change in the magnetic flux density between the measured points. The depth and width are determined through the use of a finite element model.
Findings
These calculations are the basis for determining a function that explains how magnetic flux density changes if the depth or width has changed. Jacobi's matrix is calculated using the determined functions’ analytical derivatives.
Originality/value
After wards, through the Newton-Raphson iterative procedure using the finite element method calculation results, the crack-depth and width can be obtained, this being one of the objectives in this paper. The suitability of the presented method was verified by the experimental example.
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Léa Maurice, Denis Prémel, József Pávó, Dominique Lesselier and Alain Nicolas
The purpose of this paper is to describe the development of simulation tools dedicated to eddy current non destructive testing (ECNDT) on planar structures implying planar…
Abstract
Purpose
The purpose of this paper is to describe the development of simulation tools dedicated to eddy current non destructive testing (ECNDT) on planar structures implying planar defects. Two integral approaches using the Green dyadic formalism are considered.
Design/methodology/approach
The surface integral model (SIM) is dedicated to ideal cracks, whereas the volume integral method is adapted to general volumetric defects.
Findings
The authors observed that SIM provides satisfactory results, except in some critical transmitting/receiving (T/R) configurations. This led us to propose a hybrid method based on the combination of the two previous ones.
Originality/value
This method enables to simulate ECNDT on planar structures implying defects with a small opening using T/R probes.
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Fabienne Touchard, Michel Boustie, Laurence Chocinski-Arnault, Pedro Pascual González, Laurent Berthe, Davi de Vasconcellos, Luigi Sorrentino, Pawel Malinowski and Wieslaw Ostachowicz
The purpose of this paper is to study the damage induced in “green” and synthetic composites under impact loading.
Abstract
Purpose
The purpose of this paper is to study the damage induced in “green” and synthetic composites under impact loading.
Design/methodology/approach
The study was focussed on epoxy-based composites reinforced with woven hemp or glass fibres. Six assessment techniques were employed in order to analyse and compare impact damages: eye observation, back face relief, terahertz spectroscopy, laser vibrometry, x-ray micro-tomography and microscopic observations.
Findings
Different damage detection thresholds for each material and technique were obtained. Damage induced by mechanical and laser impacts showed relevant differences, but the damage mechanisms are similar in both types of impact: matrix cracks, fibre failure, debonding at the fibres/matrix interface and delamination. Damage shape on back surfaces is similar after mechanical or laser impacts, but differences were detected inside samples.
Originality/value
The combination of these six diagnoses provides complementary information on the damage induced by mechanical or laser impacts in the studied green and synthetic composites.