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Gérard Crosland

Bio: Gérard Crosland is an academic researcher from Valeo. The author has contributed to research in topics: Digital image correlation & Acoustic emission. The author has an hindex of 2, co-authored 7 publications receiving 29 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors used both digital image correlation and acoustic emission measurements to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test, which is a continuous fibre-reinforced friction material used in car clutches.
Abstract: Non-linear stress–strain behaviour under monotonic loading can be caused by continuous damage. In order to understand this non-linearity, simultaneous strain and damage measurements were taken on composite specimens using digital image correlation and acoustic emission as these techniques give valuable local information. The latter is essential in the case of inhomogeneous or anisotropic materials, such as continuous fibre composites. On the one hand, digital image correlation gives access to full field strain and on the other hand, acoustic emission recording can be used for damage monitoring and location if, at least two sensors are placed on the specimen under loading. In this work, these two techniques were combined to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test. The composite is a continuous fibre-reinforced friction material used in car clutches. These measures were used to understand the non-linearity of the stress–strain curve of the as-received material as well as detect volume damage after thermal cycling. In depth study of the strain field and acoustic emission events location revealed a correlation between non-homogeneous damage kinetics throughout the specimen and the evolution of the strain distribution.

16 citations

08 Jul 2014
TL;DR: In this article, the authors combine Digital Image Correlation (DIC) and Acoustic Emission (AE) measurements to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test.
Abstract: Certain material have a non linear stress-strain behaviour under monotonic loading. This non linearity can be caused by continuous damage. To highlight this phenomena simultaneous strain and damage measurements should be taken. When working with inhomogeneous or anisotropic materials, such as continuous fibre composites, local information is essential. On the one hand, full field strain data can be obtained with Digital Image Correlation (DIC). On the other hand Acoustic Emission (AE) recording is a method that can be used for damage monitoring and location if, at least two sensors are placed on the specimen under loading. The aim of this work is to combine these two techniques to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test. This composite is a continuous fibre reinforced friction material used in car clutches. These measures were used to understand the non linearity of the stress-strain curve of the as received material as well as detect volume damage after thermal cycling.

11 citations

Patent
29 Sep 2005
TL;DR: Clutch lining is a friction material consisting of friction material covered, at least in part, with a coating made of an organic / inorganic hybrid material, the organic and inorganic groups having covalent or ionocovalent bonds there between as discussed by the authors.
Abstract: Clutch lining comprising a friction material covered, at least in part, with a coating made of an organic / inorganic hybrid material, the organic and inorganic groups having covalent or ionocovalent bonds therebetween.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used Digital Image Stereo-correlation (DISC) to determine the coefficient of thermal expansion (CTE) of an annular shaped continuous fiber composite with organic matrix (thermo set resins) which transmits the torque from the engine to the wheels.
Abstract: In dry clutch systems, the clutch facing is an annular shaped continuous fibre composite with organic matrix (thermo set resins) which transmits the torque from the engine to the wheels. In use it is submitted to thermo-mechanical cycling. Due to the composite fibre organisation, the strain field under thermo-mechanical loading is not homogenous. Full field data is needed to describe the material behaviour. Digital Image Stereo-Correlation (DISC) was used to determine the coefficient of thermal expansion (CTE) of the material. To determine the effect of temperature and cyclic loading on the mechanical properties, the composite was subjected to different thermal cycles. The material properties are modified with increasing temperature and number of cycles. These results were confirmed by dynamic mechanical analysis which showed thermal ageing of the resin. The local information given by the strain fields revealed a non uniform evolution of the material properties with thermal cycling.

2 citations

Patent
Loic Adamczak1, Gérard Crosland1, Franck Delavente1, Matthieu Morpain1, Patrice Malagnac1 
24 Sep 2013
TL;DR: In this article, the friction disc of a clutches is described as a friction disc comprising at least two opposed annular friction linings (2, 2') each one fixed to a backing (4, 4'), and elastic means arranged between the backings so as to allow them to be brought closer together or further apart axially.
Abstract: The invention relates to a friction disc (1) of a clutch comprising at least two opposed annular friction linings (2, 2') each one fixed to a backing (4, 4'), and elastic means (3) arranged between the backings (4, 4') so as to allow them to be brought closer together or further apart axially. Each backing (4, 4') comprises fixing a tongue (6) for attachment to a central hub (12), situated at the internal periphery of the backing (4, 4'). Each fixing tongue (6) is held axially between the hub (12) and a clamping washer (18) fixed to the hub (12) to prevent the tongue (6) from deforming during operation.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a series of tensile tests on laminates with various fiber orientation angles and specimens with different notch diameter/width (D/W ) ratios are designed and tested to determine the stress concentration factor (SCF), failure process, delamination, and tensile strength degradation of aluminum as well as in E-glass laminated plates.

73 citations

Journal ArticleDOI
TL;DR: In this paper, the location of acoustic emission (AE) in loaded polymer composites can be used to get a deeper insight into the onset and growth of damage, and associated failure events and sequences.
Abstract: This review aims at showing how the location of acoustic emission (AE) in loaded polymer composites can be used to get a deeper insight into the onset and growth of damage, and associated failure events and sequences. Different location methods (experimental and theoretical) are briefly introduced along with AE characteristics in time and frequency domains. Linear (1D), planar (2D), and spatial (3D) locations of AE are examined through selected examples. The cited works demonstrate the versatile use of AE. Apart from damage and failure assessment, AE can be used to reconstruct crack growth, and thereby help determine the accurate fracture mechanical parameters. Unlike the detection of the development of damage, the identification of failure mechanisms by analyzing selected AE signal parameters, including their clustering, requires further research. Unraveling the failure mode is, however, a key topic with respect to structural integrity, residual strength, and lifespan expectation of composite par...

62 citations

Journal ArticleDOI
TL;DR: In this paper, the damage and failure of carbon/glass epoxy hybrid woven composites under tensile loading based on acoustic emission signals is analyzed in their practical uses, and the authors propose a method to detect the failure of these composites.
Abstract: Understanding the damage and failure of carbon/glass epoxy hybrid woven composites under tensile loading based on acoustic emission signals is a challenging task in their practical uses. In this st...

33 citations

Journal ArticleDOI
TL;DR: In this paper, a tensile test on carbon fiber reinforced laminates with glass and carbon fibre reinforced tab materials was conducted with concurrent monitoring of mechanical behavior of specimens through digital image correlation and acoustic emission techniques, and the experimental tests were numerically simulated through the finite element method in conjunction with a progressive damage analysis.
Abstract: Determining the precise tensile strength of carbon fiber reinforced polymer matrix composites is very important due to their anisotropic properties. In this study, tensile tests are carried out on carbon fiber reinforced laminates with glass and carbon fiber reinforced tab materials. Tests are conducted with concurrent monitoring of mechanical behavior of specimens through digital image correlation and acoustic emission techniques. Remarkably, the full field strain maps obtained through digital image correlation show that there is a relationship between uniformity of strain field at gauge length and tab material used for tensile tests. Three distinct stages of acoustic emission activity are determined, in which the duration of second stage changes significantly depending on the tab material used for tensile test. Finally, the experimental tests are numerically simulated through the finite element method in conjunction with a progressive damage analysis. A good agreement between the numerical and experimental results is obtained.

32 citations

Journal ArticleDOI
TL;DR: In this article, a passive structural health monitoring (SHM) method capable of detecting the presence of damage in carbon fiber/epoxy composite plates is developed, which requires the measurement of strains from the considered structure, which are used to set up, train, and test artificial neural networks.
Abstract: In this paper, a passive structural health monitoring (SHM) method capable of detecting the presence of damage in carbon fibre/epoxy composite plates is developed. The method requires the measurement of strains from the considered structure, which are used to set up, train, and test artificial neural networks (ANNs). At the end of the training phase, the networks find correlations between the given strains, which represent the ‘fingerprint’ of the structure under investigation. Changes in the distribution of these strains is captured by assessing differences in the previously identified strain correlations. If any cause generates damage that alters the strain distribution, this is considered as a reason for further detailed structural inspection. The novelty of the strain algorithm comes from its independence from both the choice of material and the loading condition. It does not require the prior knowledge of material properties based on stress-strain relationships and, as the strain correlations represent the structure and its mechanical behaviour, they are valid for the full range of operating loads. An implementation of such approach is herein presented based on the usage of a distributed optical fibre sensor that allows to obtain strain measurement with an incredibly high resolution.

30 citations