Ali Mkaddem

Bio: Ali Mkaddem is an academic researcher from Arts et Métiers ParisTech. The author has contributed to research in topics: Glass fiber & Machining. The author has an hindex of 14, co-authored 43 publications receiving 705 citations. Previous affiliations of Ali Mkaddem include ParisTech.

Recent advances in drilling hybrid FRP/Ti composite: A state-of-the-art review

Abstract: 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.

A micro–macro combined approach using FEM for modelling of machining of FRP composites: Cutting forces analysis

Abstract: Experimental investigation of machining is cost prohibitive. The number of parameters to control, the exhaustive material characterisation and the time consuming procedure to determine the mechanical responses like cutting forces restricts experimental studies. In this context, finite element analysis can be a feasible tool for studying the various responses in machining. This paper presents an attempt to investigate orthogonal Machining of Unidirectional Glass Fibres Reinforced Plastics (UD-GFRP) using Finite Element (FE) simulation. The simulation uses the Tsai-Hill theory to characterise failure in plane stress conditions and orthotropic behaviour. The model incorporates adaptive mesh technique and density. The material is modelled as an Equivalent Orthotropic Homogeneous Material (EOHM). A simulation scheme entailing fibre orientation, depth of cut and tool rake angle is constructed for investigating the cutting and thrust force developed during machining. The numerical results are compared to [Nayak D, Bhatnagar N, Mahajan P. Machining studies of UD-FRP composites – part 1: effect of geometrical and process parameters, Mach Sci Technol 2005;9:481–501; Nayak D, Bhatnagar N, Mahajan P. Machining studies of UD-FRP composites – part 2: finite element analysis, Mach Sci Technol 2005;9:503–528.]. Comparison indicates that the model provides satisfactory prediction of the cutting forces. The relations between material properties, tool geometry and process parameters are discussed.

Fiber type effect on tribological behavior when cutting natural fiber reinforced plastics

Abstract: Recently, natural fiber reinforced plastic (NFRP) materials are becoming a viable alternative to synthetic fiber in many industrial applications which do not require high structural performances. However, machining of NFRP such as milling process is almost unavoidable operation to facilitate the parts assembly in addition to the finishing of final products. The present study thus focused on the influence of natural fiber types on tribological behavior during profile milling process. Three types of short natural fibers (bamboo, sisal and miscanthus) reinforced polypropylene (PP) composites are investigated. The quality of NFRP machined surface is quantified using a multiscale analysis based on wavelets decomposition. The natural fiber effects related to the machined surface quality is hence identified at all scales from roughness to waviness. The bamboo fibers reinforced plastics which exhibit high contact stiffness show the smoother surface finish after machining. Therefore, the multiscale surface roughness is used as descriptor of natural fiber influence on the machining mechanisms and to establish the cutting signature of NFRP materials.

Wear resistance of CVD and PVD multilayer coatings when dry cutting fiber reinforced polymers (FRP)

Abstract: This work discusses the performance of multilayer coatings in dry cutting fiber reinforced polymers. The cutting tests were performed on unidirectional carbon/epoxy and glass/epoxy specimens with 45° fiber orientation using both Chemical Vapor Deposited (CVD) and Physical Vapor Deposited (PVD) multilayer coatings with neatly different composition, grain size and substrate-to-coating adherence. CVD TiCN/Al2O3/TiN with low adherence (CVD-L), PVD TiAlN/AlCrO with medium adherence (PVD-M) and PVD TiN/TiAlN with high adherence (PVD-H) inserts were considered for experimental tests. Scanning Electron Microscope (SEM) was utilized to characterize the flank wear patterns. The apparent friction coefficient dealing with the material removal process was deduced from cutting forces measured using Kistler piezoelectric dynamometer. The adhesive frictional signature was examined on both new and worn inserts through series of micro-scratch tests using Atomic Force Microscope (AFM). While abrasion mechanisms dominate the flank wear upon all inserts, the abrasion mode transforms from mild to severe depending upon coating layer characteristics. Regular inspections on the worn face demonstrated that the fail of first-deposited coating layer characterizes a threshold point from which the insert behavior drastically changes. The change in forces and friction tendencies' slopes beyond threshold proves that fiber phase abrasiveness dominates wear mechanisms irrespective to coating type.

Analytical modeling of residual stress and the induced deflection of a milled thin plate

Abstract: Predictions of residual stress-induced deformations on thin aerospace parts are still among the most challenging and relevant problems in engineering applications. In this paper, a new methodology based on analytical modeling of machining mechanics is introduced in order to predict thin plate deflection induced by residual stresses given material attributes, process configurations, and parameters. The model uses an elasto-plastic constitutive behavior algorithm to predict the plastic stress, strain, and thus residual stresses. A relaxation procedure is applied upon residual stresses in order to quantify the elastic deflection when the plate is unloaded from cutting forces. Experimental validations are presented on multi-pass milling of aerospace grade aluminum alloy Al7050-T7451. The newly developed analytical model shows promise to predict the residual stresses and the thin plate deflection profile under various cutting conditions.

A review of mechanical drilling for composite laminates

Abstract: Composite laminates (CFRP, GFRP, and fiber metal composite laminates) are attractive for many applications (such as aerospace and aircraft structural components) due to their superior properties. Usually, mechanical drilling operation is an important final machining process for components made of composite laminates. However, composite laminates are regarded as hard-to-machine materials, which results in low drilling efficiency and undesirable drilling-induced delamination. Therefore, it is desirable to improve the cost-effectiveness of currently-available drilling processes and to develop more advanced drilling processes for composite laminates. Such improvement and development will benefit from a comprehensive literature review on drilling of composite laminates. This review paper summarizes an up-to-date progress in mechanical drilling of composite laminates reported in the literature. It covers drilling operations (including conventional drilling, grinding drilling, vibration-assisted twist drilling, and high speed drilling), drill bit geometry and materials, drilling-induced delamination and its suppressing approaches, thrust force, and tool wear. It is intended to help readers to obtain a comprehensive view on mechanical drilling of composite laminates.

Modeling of machining of composite materials: A review

Abstract: This paper provides a comprehensive review of literature, mostly of the last 10–15 years, on modeling of machining of composite materials with a focus on the process of turning. The paper discusses modeling of both fiber reinforced and particle reinforced composites. Modeling studies include molecular dynamic simulations, 2-D and 3-D finite element models and the emerging field of multi-scale models. In fiber reinforced composites the focus is on glass and carbon fiber reinforced polymeric composites as well as long fiber reinforced metal matrix composites. On the other hand modeling of particulate composites is restricted to that of metal matrix composites (MMC). The paper includes recent modeling work to predict cutting forces, tool–particle interaction, cutting temperatures and machined sub-surface damage. A case study on the machining of the MMC A359 aluminum matrix composite reinforced with 20% by volume fraction silicon carbide particles is included to showcase the hierarchical multi-scale machining model.

Delamination formation, evaluation and suppression during drilling of composite laminates: A review

Abstract: Fiber reinforced composite laminates have been increasingly replacing conventional materials in various manufacturing sectors due to their extremely superior mechanical properties. Usually, mechanical drilling is an important final manufacturing process for composite laminates, whereas drilling of high-strength composite laminates is very challenging and difficult. As the most undesirable damage and challenging failure mode, drilling-induced delamination for fiber reinforced composite laminates is a hot research area of immerse engineering importance. A review on the path towards delamination-free drilling for composite laminates can significantly help researchers improve currently-available cost-effective drilling process and develop high performance drilling process. This review paper summarizes an up-to-date progress in drilling-induced delamination for composite laminates reported in the literature. It covers delamination formation mechanism, delamination quantification methodologies and measurement technologies, delamination suppression strategies (including tool design optimization, drilling conditions optimization and high performance drilling methods). This general review of drilling-induced delamination for composite laminates can be referenced as not only a summary of the current results from literature survey but also future work possibilities, giving the researchers the opportunity to deepen specific aspects and explore new aspects for reaching delamination-free drilling for composite laminates.

Machining of Carbon Fiber Reinforced Plastics/Polymers: A Literature Review

Abstract: Carbon fiber reinforced plastics/polymers (CFRPs) offer excellent mechanical properties that lead to enhanced functional performance and, in turn, wide applications in numerous industrial fields. Post machining of CFRPs is an essential procedure that assures that the manufactured components meet their dimensional tolerances, surface quality and other functional requirements, which is currently considered an extremely difficult process due to the highly nonlinear, inhomogeneous, and abrasive nature of CFRPs. In this paper, a comprehensive literature review on machining of CFRPs is given with a focus on five main issues including conventional and unconventional hybrid processes for CFRP machining, cutting theories and thermal/mechanical response studies, numerical simulations, tool performance and tooling techniques, and economic impacts of CFRP machining. Given the similarities in the experimental and theoretical studies related to the machining of glass fiber reinforced polymers (GFRPs) and other FRPs parallel insights are drawn to CFRP machining to offer additional understanding of on-going and promising attempts in CFRP machining.

Drilling in carbon/epoxy composites: experimental investigations and finite element implementation

Abstract: Drilling carbon fibre reinforced plastics (CFRPs) is typically cumbersome due to high structural stiffness of the composite and low thermal conductivity of plastics. Resin-rich areas between neighbouring plies in a laminate are prone to drilling-induced delamination that compromises structural integrity. Appropriate selection of drilling parameters is believed to mitigate damage in CFRPs. In this context, we study the effect of cutting parameters on drilling thrust force and torque during the machining process both experimentally and numerically. A unique three-dimensional (3D) finite element model of drilling in a composite laminate, accounting for complex kinematics at the drill-workpiece interface is developed. Cohesive zone elements are used to simulate interply delamination in a composite. Experimental quantification of drilling-induced damage is performed by means of X-ray micro computed tomography. The developed numerical model is shown to agree reasonably well with the experiments. The model is used to predict optimal drilling parameters in carbon/epoxy composites.