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Xu J.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | El Mansori M.,CNRS Mechanics, Surfaces and Materials Processing Laboratory
Materials | Year: 2016

In hybrid carbon fiber reinforced polymer (CFRP)/Ti machining, the bi-material interface is the weakest region vulnerable to severe damage formation when the tool cutting from one phase to another phase and vice versa. The interface delamination as well as the composite-phase damage is the most serious failure dominating the bi-material machining. In this paper, an original finite element (FE) model was developed to inspect the key mechanisms governing the induced damage formation when cutting this multi-phase material. The hybrid composite model was constructed by establishing three disparate physical constituents, i.e., the Ti phase, the interface, and the CFRP phase. Different constitutive laws and damage criteria were implemented to build up the entire cutting behavior of the bi-material system. The developed orthogonal cutting (OC) model aims to characterize the dynamic mechanisms of interface delamination formation and the affected interface zone (AIZ). Special focus was made on the quantitative analyses of the parametric effects on the interface delamination and composite-phase damage. The numerical results highlighted the pivotal role of AIZ in affecting the formation of interface delamination, and the significant impacts of feed rate and cutting speed on delamination extent and fiber/matrix failure. © 2015 by the authors. Source


Xu J.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | El Mansori M.,CNRS Mechanics, Surfaces and Materials Processing Laboratory
International Journal of Precision Engineering and Manufacturing | Year: 2016

Stacked composite CFRP/Ti is identified as an innovative structural configuration for manufacturing the key aircraft components favoring energy saving in the modern aerospace industry. Machining of this composite-to-metal alliance exhibits the most challenging task in manufacturing community due to the disparate natures of each phase involved and their respective poor machinability. Since the experimental studies are highly cost and time consuming, the numerical approach should be a capable alternative to overcoming the several technical limitations involved. In this research, an original FE model was developed to simulate the complete chip formation process when orthogonal cutting (OC) of hybrid CFRP/Ti stacks. Different constitutive models and failure criteria were implemented into the Abaqus/Explicit code to construct the entire machining behavior of the stacked composite material. The stack model was built to replicate accurately the key physical phenomena activated in the hybrid cutting operation. Special concentration was made on the comparative studies of the effects of different cutting-sequence strategies on the machining responses induced by CFRP/Ti cutting. The numerical results highlighted the significant role of cutting-sequence strategy in affecting the final machined surface morphology and subsurface damage extent, and hence emphasized the importance of selecting reasonable cutting-sequence strategy for hybrid CFRP/Ti machining. © 2016, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg. Source


Serpin K.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | Serpin K.,Renault S.A. | Mezghani S.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | Mansori M.E.,CNRS Mechanics, Surfaces and Materials Processing Laboratory
Surface and Coatings Technology | Year: 2015

Advanced belt finishing process is remarkably simple and inexpensive. The principle of operation is simple: pressure-locked shoes platens circumferentially press an abrasive coated belt on a rotating workpiece. This abrasive machining process reduces significantly surface irregularities subsequently improving geometrical quality and increasing wear resistance and fatigue life. It is therefore extensively used in automotive industry to superfinish crankshaft journals. However, the major industrial issue about this manufacturing process is its efficiency and robustness.One of the most promising ways to solve this issue is to control the distribution and morphology of the abrasive grits. Recently a new generation of abrasive belts coated with structured and shaped agglomerate grits has been commercially available. These structured coated belts with mastered cutting edge orientations promise to be more efficient as they have a better wear resistance compared to the traditional coated abrasive belt. Therefore, this work aims to discuss these assumptions and to establish the link between three structured coated belts, the surface finishes and the physical mechanisms which govern their wear performances. In particular a parametric study, based on the cycle time and the rotation speed, is lead in order to analyze the potential of each structure in terms of surface roughness improvement, wear resistance and consumed energy.The experimental results have demonstrated that, depending on the abrasive structure considered and for a same number of revolutions, modifying the cycle time or the rotation speed can lead to different surface finishes and belt's wear. © 2015 Elsevier B.V. Source


Xu J.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | Mkaddem A.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | El Mansori M.,CNRS Mechanics, Surfaces and Materials Processing Laboratory
Composite Structures | Year: 2016

Hybrid composite stack, especially FRP/Ti assembly, is considered as an innovative structural configuration for manufacturing the key load-bearing components favoring energy saving in the aerospace industry. Several applications require mechanical drilling for finishing hybrid composite structures. The drilling operation of hybrid FRP/Ti composite, however, represents the most challenging task in modern manufacturing sectors due to the disparate natures of each constituent involved and the complexity to control tool-material interfaces during one single cutting shot. Special issues may arise from the severe subsurface damage, excessive interface consumption, rapid tool wear, etc. In this paper, a rigorous review concerning the state-of-the-art results and advances on drilling solutions of hybrid FRP/Ti composite was presented by referring to the wide comparisons among literature analyses. The multiple aspects of cutting responses and physical phenomena generated when drilling these materials were precisely addressed. A special focus was made on the material removal modes and tool wear mechanisms dominating the bi-material interface consumption (BIC) with respect of investigating strategies used. The key conclusions from the literature review were drawn to point out the potential solutions and limitations to be necessarily overcome for reaching both (i) enhanced control of drilling operation, and (ii) better finish quality of FRP/Ti parts. © 2015 Elsevier Ltd. Source


Xu J.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | El Mansori M.,CNRS Mechanics, Surfaces and Materials Processing Laboratory | Voisin J.,CNRS Mechanics, Surfaces and Materials Processing Laboratory
Procedia CIRP | Year: 2016

Compared to the great interest of experimental studies on hybrid CFRP/Ti drilling, this paper provided a new contribution to study the hybrid composite machinability via the numerical approach. To this aim, the complex drilling operation was abstracted into the orthogonal cutting configuration (OCC) by considering the involved cutting sequence from one phase machining to another phase machining. The numerical model was established by incorporating four fundamental physical constituents (i.e., Ti layer, interface, CFRP layer and tool part) to simulate the hybrid cutting operation. Different constitutive laws and damage criteria were implemented to construct the anisotropic machinability of the stacked composite. The induced cutting responses including specific cutting energy (u) and induced damage formation, were precisely addressed versus the input variables. The numerical studies highlighted that the anisotropic machinability of the CFRP/Ti stack could be reflected in a "pigeon" like u polar map versus fiber orientation (θ). For minimizing the severe induced damage extent, high cutting speed, as well as low feed rate, should be adopted when machining this multi-phase material. © 2016 The Authors. Source

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