Labège, France
Labège, France

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Saleem M.,Ryerson University | Bougherara H.,Ryerson University | Toubal L.,University of Quebec at Trois - Rivieres | Cenac F.,JEDO Technologies | Zitoune R.,CNRS Clement Ader Institute
Materials Science Forum | Year: 2013

The aim of this paper is to analyze the influence of two machining processes on the mechanical behaviour of composite plates under cyclic loading. For this purpose, an experimental study using several CFRP plates drilled with conventional machining and non-conventional machining (abrasive water jet) was carried out. Digital image correlation and static tests using an Instron 4206 tester were performed. In addition, infrared thermography (IR) and fatigue tests were also performed to assess temperature and damage evolutions and also the stiffness degradation. Fatigue results have shown that the damage accumulation in specimens drilled with conventional machining was higher than the abrasive water jet ones. Furthermore, the endurance limit for plates drilled conventionally was approximately 10% higher than those drilled with abrasive water jet. This difference was related to the initial surface integrity after machining induced by the difference in the mechanism of material's removal between the two processes. The difference in surface texture was responsible for the initiation of stress concentration sites as evident from IR camera's stress analysis. This was confirmed by SEM tests conducted after a destructive sectioning of the specimens before fatigue testing. © (2013) Trans Tech Publications, Switzerland.


Cenac F.,CNRS Clement Ader Institute | Zitoune R.,CNRS Clement Ader Institute | Collombet F.,CNRS Clement Ader Institute | Deleris M.,JEDO Technologies
Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications | Year: 2015

The abrasive water jet is a 30-year old technology widely used to compete conventional machining capabilities. While it is mainly used for cutting applications, studies demonstrated its ability for milling, turning and micro-piercing. But as long as abrasive water jet issues are not clearly identified and analyzed, these processes can hardly be industrialized. This paper proposes an innovative methodology for studying abrasive water jet milling. Its main purpose is to consider the machined depth as an experimental factor and the feed rate as a product. A large-domain full-experimental-design on the pressure, the orifice diameter, abrasive mass flow rate, the milled depth and the feed rate on milling of aluminum 2024 T3 is presented. Finally, a mathematical model on the optimal abrasive mass flow rate and the milled depth are developed. The good correlation of these models within the large experimental domain suggests the pertinence of the proposed methodology. © 2013 IMechE.


Collombet F.,CNRS Clement Ader Institute | Crouzeix L.,CNRS Clement Ader Institute | Cenac F.,JEDO Technologies | Grunevald Y.-H.,Composites Expertise and Solutions | And 3 more authors.
Revue des Composites et des Materiaux Avances | Year: 2013

Experimental protocol of Abrasive Water Jet (AWJ) milling is presented for composite material machining. It deals with a model concerning on one side, the optimal abrasive flow versus pressure, the diameter of tube and machined depth, and on the other, the feed rate versus the pressure, the tube diameter, the ratio of abrasive optimum flow and the required depth. Carbon/epoxy coupons are machined, repaired, and tested to estimate behavior of a step-lap repair. Digital Image Correlations as well as FEM simulations are used to study the release of residual stresses during machining. Machined plates are repaired by laying up same stack of epoxy-carbon plies with one ply shifting and cured in autoclave. Experimental results in traction are discussed between repaired coupons and healthy ones. © 2013 Lavoisier.


Crouzeix L.,CNRS Clement Ader Institute | Davila Y.,CNRS Clement Ader Institute | Collombet F.,CNRS Clement Ader Institute | Douchin B.,CNRS Clement Ader Institute | And 3 more authors.
ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials | Year: 2012

An innovative repair process and evaluation are proposed. Firstly, the originality of this work consists on the process used for the repair milling: an Abrasive Water-Jet milling. A doublestep lap coupon is chosen to demonstrate the feasibility of the milling process. This specimen is made of M10.1/38%/UD300 CHS 460 from Hexcel Composites. After milling, the removed material is reconstructed laying up the same prepreg material with a one-ply shift in the staking sequence. A Redux 609 adhesive film is used to ensure a correct bonding on the interface. Secondly, the originality concerns the mechanical characterization of the repair quality assessed through an innovative multi-axial mechanical test. It allows to choose multiaxial loadings according to the requirement. The selected test is a combined bending and compression test. Finally, results of mechanical tests are presented and discussed.


Sultan T.,CNRS Clement Ader Institute | Gilles P.,CNRS Clement Ader Institute | Cohen G.,CNRS Clement Ader Institute | Cenac F.,JEDO Technologies | Rubio W.,CNRS Clement Ader Institute
Mechanics and Industry | Year: 2016

Abrasive water jet milling (AWJM) is a new way to perform controlled depth milling especially for hard materials, but it's not yet enough reliable because of large variety of process parameters and complex footprint geometries that are not well mastered. In order to master the milling device in AWJM, a deep study on the footprint of a single path of the cutting head should first be considered. The flow of the AWJ and the distribution of abrasive particles coming out of the jet are related to the profile measured on the footprint. In this study, experiments were made on titanium alloys specimen to compare several theoretical models to the measured profile of the footprint. This study establishes new models to fit the incision profile taking in consideration the behavior of the abrasive particles impacting the workpiece. © AFM, EDP Sciences 2016.


The invention relates to machine a component made of composite material in order to eliminate singularities, defects or damage to the component using a method that is repeatable and adaptable. To do this, it is proposed that the defects and their type be identified by image processing of the surface of the component and that the local machining rates at which the plies are machined be regulated at the function of this identification. According to one embodiment, a system (10) for the ply-by-ply machining of defects of a component made of composite material includes a numerical data processing unit (1) combined with a sweep control (2) that commands the sweep of a high-pressure water jet machine (20), and an image formation assembly (3) including an image capturing device (30, 31) connected with the numerical processing unit (1). The processing unit (1) includes regulating devices (11, 13) indexing local sweep rates, by convergence of brightness levels (NB) from the successive sweeps, these being formed by the image capturing assembly (3) toward making the brightness uniform according to a model (Mr) correlating brightness to ply state typology identification (BT) that can be supplied by a library (4). The correlation data (BT) and brightness levels (NB) are stored in memory modules (12, 14) of the processing unit (1).


The invention relates to implement the sealing, porosity and sweeping functions, combined. For this purpose, the present invention proposes to confine the waste and to suction the waste at the ejection head by means of a sufficiently flexible connection, such as to remain in contact with the machining area. According to an embodiment, a portable machining machine (1) operated by a pressurized jet (112) includes a waste recovery system (5), an injection head (11) which is provided with a nozzle (111) having an axis (A1) that is substantially perpendicular to the surface to be machined (4a) and which is driven by a digitally controlled two-axle guide system, the ejection head (11) being extended by an enclosure (12) to the surface area to be machined (4a). In addition, the enclosure (12) comprises a tubular portion (121) consisting of two walls (12a, 12b) which slide coaxially along the axis (A1) and a double-pivot articulation device (123). The enclosure (12) has a porous annular wall (124) in a plane substantially perpendicular to the axis (A1) of the nozzle (111), said annular wall (124) having sufficient resilience to keep the enclosure (12) in permanent sealing contact with the surface to be machined (4; 4a, 4b).

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